Seen the tears happen. And you create an imbalance if you go for too much volume using the mix grip.
Have no issues with straps. Even competitors use them.
I use mix grip, only when I’m doing my peak 1-rep set or set of reps. Doing double overhand will force you to lower the weights at first, but your grip begins to adapt. Hook grip is an option, but a lot of people are too bothered by the pain. College kids have a limited amount of time to train. No point in keeping that weight too low, because their thumb hurts too much. Or, they can’t go anywhere near their max with straps, since their grip hasn’t adapted with a double overhand.