Certainly not a sole option. As far as first option from on top, I think it depends on what kind of crab ride you're talking about. If you're talking about a 2-on-1 crab, then no. We run the tight-waist/half nelson crab, where you can run the half or get a short hook-pin, get the two-on-one from the bottom guy fighting the half, or just ride the tilts and rack up points. So for us it more or less functions as a platform.
I think the mentality of the wrestler has a lot to do with what works for them as well. Different things work for different kids.