So there is some sort of hierarchy of instruments or a dumb sync track pre-recorded.
Lets say the delay is 15 seconds, you hear the composite, including your part delayed, and you "think, cool, I played the right thing at the right time, I'll keep going with my same assumptions" or you hear "my part was way off, but the rest sounded decent enough, better do something different."
The part where everyone is just playing terribly isn't a concern or doesn't manifest because you've got a bunch of intermediate or better musicians playing.
This literally is marketed as a speech jammer.
The amount of times I'm tripping up on my own words because the last thing I said is blaring out a friends/family mobile speakerphone and then back into the mic is disappointing on all levels, to say the least.