Yes, attaching a track to a movie causes more people to actually hear that track and will generally garner interest in that track and ultimately, the album. The drawback is that it would give the perception that Will is just another actor trying to drop a CD, and worse, in connection with his movie. Will would sell more, but the album would come into question, at least initially. With something like Lost and Found, all questions would be dismissed pretty quickly, but with something like Born 2 Reign, Will could come out looking pretty bad.
The best practice is to not use any gimicks and let the music speak for itself, unless it's a really good album like Lost and Found. In general though, Will should try to separate movies from music as much as possible.