I'm learning to serve right handed, and an eastern forehand gives instant gratification and allows me to play at the 3.5 level.
If I switched to conti, it would take a couple months of practice and play before I can serve to the side I need to, and to hit a decent fast first serve with a consistent second serve.
Meanwhile, I'd be stuck only practicing, not playing.
Instant gratification is worth something, since I play left handed, and don't practice at all. I"m certainly NOT going to go out and practice my rightie serves with conti grip.