Because people, including you in your post, talk about him like he's something more than the 2nd string PG on a bad team or a 3rd string PG on a decent team.
He brings okay passing, speed, and hustle, but he's defensively weak for all his ball hawking and couldn't shoot a lick last year. Defensive liabilities who can't score don't do much for your team.
He absolutely needs to hit 37% or so on his threes to stay on the court, finishing a layup or two would also be big.