Connecting to Facebook - What's the point?

Just wondering why it asks you if you want to log in via facebook when you sign in on here now?
Are there any extra features you get from doing this?
And are your facebook friends just going to get their feeds spammed with "FACEBOOK USER IS READING; Danny's Big Old Car Project"
Just curious

It unifies your login by using you Facebook account.
It also gives you the option to syndicate out your posts on here to either the Owners club group on Facebook or your own wall.

Kind of a take it or leave it feature - some wanted it and the rest don't care.