My favorite gym has a (non-adjustable) hand crack, finishing with an overhanging fist crack. It definitely helped me improve my technique (especially my foot jams). But I was one of only three people I ever saw climbing it. And I say "was" because I've only climbed it like once in the last two years, and I'm not sure I've seen anyone else climbing on it it the last year or so.
. . . (I've never seen a crack at an indoor gym in France or Italy, but in Germany the biggest Munich Thalkirchen DAV gym has some several non-adjustable cracks).
"Adjustable" is a good idea, because I say the finish is a fist crack, but I've got big hands. I think for people with small hands, it's barely climbable at all.
Which gets to the other reason why I doubt many new gyms are going to bother with cracks. Because it's rather difficult to make crack sequences which are "fair" for _competitions_ -- a crack sequence will typically be much harder or easier depending on hand size.
While it's easier to make pinch-hold and compression moves "fair" for a wider range of competitors.
Especially with indoor climbing now as an Olympic sport, I'll guess that indoor gym design will be more driven by competition, and less by resemblance to outdoor climbing. And since most indoor gym climbers nowadays are much more interested in Sport climbing than Trad, there's even _less_ interest in preparation for outdoor _crack_ climbing.
One famous French(?) climber said: "When the back of the hand touches the rock, true climbing is over".
I do not agree, and I enjoy finding opportunities for jamming moves outdoors -- but who cares what I think.
Ken
Post edited at 04:55