You're not attracted to her and you know you never will be. So is it wrong to accept her dinner invite simply in order to get back in the game?
That's the underlying issue in this article, where one guy talks about "practice dating" -- the idea of going out with people primarily to understand how the opposite sex works, rather than viewing every date as the beginning of a serious commitment.
I think the beginning stages of any relationship are kind of like "practice." It's very rare that two people go into a first date with a mutual expectation they'll be together forever.
There's been times when after moving to a new city, I've accepted a date invitation primarily under the mentality of, "At least I'll meet somebody new."
But using someone just as a way to beef up your conversation skills? Seriously, just buy a book or something.