The basic issue that paper tape is hard to edit. In theory you can cut the existing tape and splice in a new section, but in practice there is no easy way to find the correct location except by printing the contents of the tape (at 10 characters per second) and searching by hand. People did learn to read the tape hole patterns (they were no harder to learn ...
Punch cards long long long predated paper tape.
But there's a practical consideration you're not thinking of. If you had ever used punch cards and paper tape, you'd know:
Punch cards can be dropped, and they scatter on the floor. Then you pick them up, put them all face up (by the printing on them) in the same orientation (with the one corner that's cut ...
Punch cards and paper tape are suited for different tasks.
Punch cards work better when the size of the data is not known in advance. How long would you manufacture the unpunched paper rolls? If the roll is too long, you are wasting paper and increasing costs. If the roll is too short, you either have to splice it together, or have the operator load more ...
To add one more dimension to the answers already given: cards are easier to handle, whether by operators, or in a cafeteria (user self-service) system.
A high-speed card reader has an input hopper and an output stacker. After reading a deck of cards, you've got a deck of cards in the stacker.
The high-speed paper tape readers of my acquaintance would do ...
If you want to read it as octal, having the low order 3 bits grouped together is handy. Many of the early ASCII tables showed the codes in octal. HEX makes more sense once your computers begin to work on 8 bit bytes, but earlier computers had units like 36 bit words that were divisible by 3, and this led people to use octal for a few years.
Punched cards ...
What I'm wondering is: why punch cards instead of paper tape?
Because it was already there?
Early commercial computers were made to replace tabulating machines. To do so they had of course to be able to read (and write) punch cards. There was no need for paper tapes.
Well, ok, paper tape was first, as the Zuse machines used them and some other experimental ...
An other nice thing about punch card is that you can use them, or better use a small pack of them, in another program. Some sort of copy/pasting.
I remember packs of hundrands cards with colored cards slipped from time to time to physically separate subprogrames that could be reused elsewhere.
Was there any equipment which could directly print out the program or data on a stack of punchcards, without first loading the deck into a computer?
No. Such a dedicated device did not exist.
Neither during the time pf punch card processing (pre-electronic computer) nor and even less after electronic computers became a thing. The simple reason is that there ...
The answer is a clear YES.
What was the question again?
More serious, there is no single answer.
It depends on
Application the data were meant for
Or if there's a checking at all
Already the question if something is octal or BCD or character does quite differ across applications and platforms.
Then there is the factor of ...
Was it ever possible to take an actual existing punch card reader, and hack a connection to hook it up to a computer?
No, why? The existing tabulating machine was all about parallel processing.
Or was it the case that yes the existing cards could be reused, but to use them with computers required designing and building all new equipment?
No. Of course not....
There was paper tape and paper tape. For example, see Here for fan fold papertape. This could be read in by a conventional ASR33 type teletype reader but often was read by a specialized high speed reader. The fan folded tape could be fitted on one side and read through quickly. It could then be rewound almost like a tape from one side to the other. The first ...
Another advantage of cards over tape: Ease of setup for batch processing:
With cards, it is a trivial effort to pile up multiple stacks for successive scanning.
With tape, either you have to splice multiple tapes together in sequence and respool (a process fraught with peril of tearing), or dismount each tape and mount the next, which takes up a fair ...
Back in 1962, when I was in a class to learn machine "coding" on a Burrough's 205A, the first 6 instructions were hand entered with toggle switches on the actual computer rack. They were the "start up" instructions that made the 8 bit computer smart enough to read the paper tape accessory on the side of a KSR-33 teletype. The 205A had ...
As pointed out in the other answers, trying to "edit" paper tape directly is awkward.
One solution is to have a batch editor that reads an edit tape into memory, then use the batch edit commands to read a source tape and punch an edited tape, according to the edit commands. A second tape reader could be used to reduce memory requirements.
A more ...
Economics. Making a long roll is more expensive than cards. Shipping cubes is more space efficient than cylinders. If one section of the tape is damaged, it can't be sent to customer, but if cards are damaged, such as with oil from cutting machine, just replace them with non-damaged cards.
Structure: You can make a card stiffer, and it ...
A few additional side benefits of punched cards as opposed to punched paper tape:
Punched tape was supplied on rolls of particular lengths. A roll of
tape could only accommodate a certain amount of data. A stack of
cards could be any length.
Paper tape wasn't as robust as punched cards - the paper was thinner
than that used for cards. Punched cards were ...
Reading a single punched card is not very difficult. You just need enough photodiodes or spring pins to sense all the rows in one column, and a mechanism to advance the card precisely from one column to the next. The tricky part is handling many cards in sequence, and keeping them in sequence in the output tray for later reuse.
IBM had already solved these ...