Viqsi
"that chick from Ohio"
It drives me crazy for two reasons:Conversely I only know 1UPT. It's baked into my strategy approach. It'd be fun to try without it.
1) in combat, I like to commit logical groups of forces together with different specialties, and it's kind of difficult/impossible to do that with 1UPT and keep track of who's associated with what. At least for me.
2) I love love love love combining workers on one tile enhancement to speed them up then spreading them back out as needed. (I had heard some comments that Civ6 had fundamentally changed how they work but frankly I've never tried Civ6.)