I've seen the scopes on crossbows and pin sights as well and I would agree they are fairly easy to get dialed in and seem to stay dialed in well. But I feel the same way about my compound sights as well, mine stay dialed in well and if I do make changes it usually only takes a short amount of time to dial them back in.

I do think practice is important for both but would agree it is probably more important with my compound and definitely my recurve.