I literally never had the thought, "If only I could type faster, I could get this done more quickly..."
I think few slow typists would have had that literal thought either. I know I never did as I approached up to my ceiling of about 70wpm.
If you're a heavy vi user, it's probably not worth it, but if you weren't and you did a lot of typing it might be worth it to see if it helps with comfort. Also, what's wrong with the fun of trying new things?