The locking mechanism makes string change simple and quick. The advantage for every day is that the turn ratio per tone change is the same for all strings. So even a good guitar becomes only great with these tuners. Other brands offer also locking mechanisms, but not the adapted rear ratio.
I don't play very hard, but I do not believe that locking tuners give more stability for your tuning. If this would be true, the strings are supposed to slip on normal tuners, which should not be true if your strings are fixed with 2 turns or a bit more. Besides this, temperature makes a big difference for the tuning, where the locking mechanism offers no change.
Even with locking mechanism, I add always 1 to 3 turns for every string to better fix it.