I fully agree with you, and never thought Bolden to be anywhere close to the bubble this past summer. He's shown the ability to play on all of the ST units quite effectively, with the capacity to run the ball as a lead back should injury occur. He also showed enough of an ability to catch balls out of the backfield, hauling in 21 receptions as recently as a couple of seasons ago.
That said, he is quite unspectacular while doing so, which is why some posters do not feel as though he is an asset to the team. Unfortunately, he has not looked too hot so far this season, although it's early yet.
Either way, I do agree that he fits into the category of a reasonably priced, veteran with experience in our system, and the capacity to work hard and contribute in many phases. Those are all traits that Belichick admires.