It is probably important that they have had a couple of Oh Sh!t moments too in order that they can understand how they react to an emergency.
I agree self rescue and panic mitigation is an important component of being a candidate for solo diving. Not everyone has the prerequisites I've noticed. I have no confidence 100 dives count for much in that regard. At best it does provide a nice backdrop for enjoying nice relief for peace solo diving with a strapped on pony brings. (I like my pony)
Cameron