If he wasn't a slow midget, he wouldn't be a backup, he'd be starting somewhere.
He's a small, slowish backup PG who can spot up, shoot off the dribble and run an offence. Works hard at the defensive end as well, though is definitely underpowered there against anyone with legit quicks or size. In 15-20 backup minutes a night he's not going to hurt you, which I think we all saw the value of in the Malachi Flynn era here. Pritchard is probably the 2nd-3rd best backup PG in the east and he makes poverty wages by NBA standards to be functionally useful.
If Boucher was expiring this year, and Boston was dangling that, I'd consider taking it and then look to move Dennis + Gary + stuff of value in for a shooting guard solution.