An automatic locker in the rear, or front for that matter, does not increase tire wear. This isn't just an internet opinion, it's a fact. The potentially annoying qualities of an automatic locker in the rear come from how it differentiates, not because it locks up. When going around a corner the locker differentiates by the outside tire freewheeling and running ahead of the inside tire, so no tire scuffing, but you can feel some pushing now and then since only the inside tire is being driven. When you go around a sharper corner, typically when starting from a stop and accelerating, the inside tire can chirp because it's the one getting all the power. It doesn't help that when cornering the weight transfers to the outside so that inside tire also has less weight on it making it easier to spin and chirp. You'll notice that if you're a little easier on the throttle when accelerating slightly around a corner there won't be any chirping. Also, the chirp, chirp, chirp is because the inside tire can spin a little until it catches up with the free spinning outside tire, then the outside tire spins ahead again, and the inside tire chirps again until it catches up again. If you actually gave the vehicle enough throttle to lock the locker then there wouldn't be a chirp, there would be squealing from both tires spinning.
So, ease the throttle a little around corners to minimize the chirping, and don't worry about tire wear because the locker is not locking up.
Regarding turning sharper on the trail, it definitely helps to have one end unlocked. However, you'll turn sharper with the rear open and the front locked than you will with the front open and the rear locked. Conventional wisdom on this subject has recently been proven wrong, and more and more people are putting the selectable locker in the rear rather than in the front and getting better street manner and tighter turning on the trail. When the front is locked it just pulls around the corner, but when the rear is locked it tries to push the vehicle straight. Of course, when both are locked the scuffing makes it harder to turn. But, front locked/rear open definitely works better and turns sharper than front open/rear locked.
If you haven't done it both ways, then you just don't know how much better it is.