The balancing act the gyms, in particular, are trying to play is that knots should be both secure and easily verifiable on sight by gym staff, more or less entirely for liability reasons. A yosemite finish, or a bowline, are both dead-ass safe and in some cases better than a traced eight, but they're harder to glance at and know they're safe. That's totally fine at the crag, but it's a liability issue at the gym.