No, I never use the not symbol. But since Kmonad/Chysalis/QMK all work by mapping keycodes, and for some reason ¬ exists on standard UK keyboards, it ends up being included (at least, in the case where the OS keyboard setting is UK).
There again, perhaps it's ¬ a bad idea if I did start to use it. I'm ¬ sure I'd use it that often, but there might be some circumstances. As long as I didn't tie myself in k¬s over it.
Apart from that, out of interest what symbols do you think are unintuitive?