For those that don't know,
JiffyDOS is a ROM replacement for a Commodore 64 (and 128, I believe) and its 1541 disk drive. This ROM replacement provides OS shortcuts, faster load times, etc.
I've noticed that many Commodore 64 (and perhaps 128) users install an external switch to disable the JiffyDOS ROM and switch back to the original Commodore ROM.
What was the main reason for this? Did some games or other software programs not support JiffyDOS?
I realize a switch is a convenient way of not having to open the hardware so my question isn't on the switch...but why many users opted for a switch.