I just realized why I don't like the wedding invite via facebook.
When people send me facebook invites to things, I - along with many if not most of other people, don't really read what it is for - and just click "attending, maybe, not" to it. That is, if they check their event list at all. It seems trivial to me to put it on the same page as "Hey, so I sent you the invite a few weeks ago, but you're coming to my wedding, right?"
"Wedding" and "BBQ" should never be inter-
changable words.
Not to mention e-vites aren't physical things. So you have to factor, how much time do you give to an e-vite for a wedding? Too long, and they might forget about it entirely, too short and it will seem like bad planning. The beauty of the actual invite, is people can put it on a counter/mantle etc. until the date arrives.