Thing is, the u-turn adds very little weight and it's usually reliable, so it's no great issue to have it and never use it.
I can understand why people don't like it, it's no one-button solution but it still takes no real time or effort to go from one end of the travel to the other, and it's easily done on the move (not sure this is recommended but it's not at all hard to do)
They're not for climbing for me, or at least not just climbing, both my bikes have pretty different character with the forks at different lengths so it's about variety as much as anything else. Though being able to drop the front on the hemlock does mean I can run a more downwards-oriented setup and still get up steep stuff, avoids the compromise.