That's a pretty ignorant conclusion.
The point of this gun is that you get close, hit, and send the enemy flying. I'm guessing the sandman has decent knockback as well.
Also, I'm guessing that a scout with his energy drink, double jump, and shotgun here could easily rush into an enemy base, fire both heavy shots into a sentry gun and engineer fixing it, then rush back out before getting killed. Reload, re-boost- repeat. Things like that.
Don't insult the weapon before it even comes out. I'm sure Valve knows what they're doing, and are giving weapons that allow for all sorts of different variations of scouts.