The real, lasting, significance of the TVT was to inspire Lee Felsenstein to actually sit down and design his Tom Swift Terminal.
Lee was a sysop on the first BBS, Community Memory. The main problem with the system is that it used a $1,500 ASR-33 terminal and a $300 modem. He had already fixed the modem problem by inventing the Pennywhistle modem, which cost about $100. But the terminal remained a problem.
When he saw the TVT, he began adapting it as the basis for a low-cost glass terminal. He called and asked Lancaster why he hadn't made it into a terminal, and Lancaster replied he just didn't think of it. So Lee did, combining the TVT with a 1k RAM and a serial and (4-bit?) parallel interface. The idea was that you would put a TV on the TVT output, a keyboard on the parallel, a Pennywhistle on the serial, and then you could connect to Community Memory.
However, by the time he was getting interested in this, Community Memory was going through its death throws. He released the plans in 1974, but in the end no one ever built a Tom Swift. But the timing was just so that in less than a year of Felsenstein passing around the Tom Swift design, the Altair 8800 was launched.
Felsenstein had recently decided to share the rent on a garage with Bob Marsh so he could make a Tom Swift. Marsh wanted to make LED clocks, but when he saw the Altair he got Felsenstein to convert the TVT into the world's first video card, the VDM-1. This was done by adding 1k of memory and interface circuits to the TVT. 1k was why S-100 machines had the "odd" layout of 64-column by 16-row text display, as 64x16=1024=1k. The agreement was that if he did that, Marsh would fund the development of the terminal as a whole.
At the same time, Les Solomon decided someone should convert the TVT into a low-cost terminal for Altair owners - at that point a glass terminal cost about the same as a brand new VB Bug (Super no less). His first attempt did not go well - he took Lancaster to meet MITS, and a shouting match broke out. So he approached Marsh, and March approached Felsenstein again, and now, at long last, the Tom Swift was definitely, totally going to happen.
But when March priced out the design using an 8080, and Felsenstein did the same with his original discrete components, the difference was $10. They decided to go with the 8080, and would make it into a terminal using a terminal program in a ROM. The then packaged a generic 8080 mobo along with a VDM-1, I/O card and a power supply into a case and called it the Sol-20
The Sol-20 was first true personal computer, IMHO, as previous machines required separate terminals for output. So... depending on your point of view, although the TVT was likely only used by a few hundred people for a couple of months of playing around, it indirectly helped spawn the home computer.