Would you use facebook connect to register for a website which gives you free bitcoins?
Or would you prefer the website have it's own registration process?
Well I personally hate creating new accounts, but though Facebook....? Ehhhhh.....
If you are asking if it will be successful? Go for it.
It will. I personally don't like it, but the fact is that it will generate new users effectively.
Why not Google Authentication? Sure they do the same data mining as Facebook, but I do trust them more.