Meh.
He's just an actor in the first ones (far as I know) so I don't really care if he gives his approval or not. Toss in that he hasn't see it yet and really what else can one expect? If he trashed the idea he is just burning bridges for no reason.
Doesn't hurt his chances for appearing in future sequels as well, if this one does well 
We built this city on Rock and Roll!
So Matt Damon has given his blessing for the new film.
You only fail if you give up. - Dana Scully
Time Jesum Transeuntum Et Non Riverentum - Nick Cave
We're not just destroyers, at the same time we can be saviors. - Allen Walker