Another minus is that White can hardly go wrong: His position is extremely easy to play.
This is really the heart of it. One of the "nice-to-haves" about playing the Nf6 Scandi. should be that you expect your average opponent to burn his clock and/or make inaccuracies figuring things out.
One of the worst things you can do vs. a strong player is give your "slightly booked (Bb5+)" opponent a straightforward way of playing the position.
Another minus is that White can hardly go wrong: His position is extremely easy to play.