How many ticks it take for all the hp to be regenerated doesn't really change the MP efficiency. Of course, if that's incorrect, please explain why.

I'm still hoping you can show us an example where regen is a better choice than a normal cure in a fight that is hard enough to actually matter. All I'm seeing is you getting mad at people because they don't take your word for it when you say regen is useful without giving any good examples or mathematics to back it up.