But that's the trick. An actor who is good should be able to inhabit the role so you don't see them as the person, but as that character. It's how TV and film works. So this should be no different, for a professional. But these other people are far from professional actors.
I won't deny the acting talents of professionals. My point of contention is to have a cartoon version of a real life person there in the game; it's not Keanu acting there. If the game was a similiar case as with those late 90's games where real actors were actualy shot doing the acting (Harverster, Ripper, Phantasmagoria....), no problem. But that's not the case here. It distracts the experience in a somewhat similiar fashion as if breaking the fourth wall without it being an intended joke.