The one downside of doing 'breathe-hold dives' as a comparison is that if you're in a shorty for snorkeling you're probably not weighted, so you have to fight to get down a bit. Which then makes you not as comfortable staying down very long, so it might 'train' you that you can't safely ascend from much more depth than you can comfortably descend to from the surface. After all, your lungful of air at the surface is getting heavily compressed as you go down.
With the CESA on the other hand, expansion as you ascend means your lungs stay 'full' even as you're bubbling air out. Of course you can't do this forever as CO2 partial pressure is still increasing, and it's not safe to simply say you can 'exhale for a long time' with no consequences...but it isn't nearly the same sensation as the clench you feel when compressed lungs want to inhale. (Now that I think of it, given shallow water blackout etc. the sensation of expansion during a CESA is probably falsely comforting by comparison, isn't it?

)
I know you understand this perfectly well, spectrum, I just want to make sure that bgsnmky does. There's nothing wrong with racing to the surface from a snorkeling descent - you didn't breathe air at pressure other than at the surface, and there's no gas content issue at the depths you or I are likely to go on a free descent like that - on the other hand, there is a maximum safe ascent rate even on a CESA.
But I agree 100% the *right* solution is: proper air handling, proper breathing technique, and proper (but not excessive) buddy to buddy interaction. Equipment failures from other than neglect and lack of maintenance - just random crapouts - are rare by comparison I'm sure (<---said confidently but with utter lack of statistics to back it up).