My 22 F250 has locking hubs with auto engagement. I think I want to delete the auto engagement though because there are times when I want use 4 low without locking the front axle.
I've had manual locking hubs fail too. As long as you use 4X4 on a regular basis to keep everything lubricated automatic hubs do pretty good. The only time I've seen either type fail was when they weren't used for a long time and the lack of lubrication prevented them from locking when needed.
I've owned a 4x4 of some sort since 1976. Back when there were 3 sticks in the floor and manual locking hubs it was easy to use 2wd low range. But they used to put warning labels in the cab warning drivers not to. I watched one person snap a U-Joint doing that. I suppose if you're careful and just need to go slow and aren't trying to pull much weight in 2wd low it would be OK.
