The thing with IT is always going to be defense. Can you ever actually keep him on the floor for 36 minutes without getting killed defensively? Probably not.
He's a really productive player and you can't ask for a better sparkplug guard to come off your bench.
Maybe the Celts can get by on defense if they put him next to Smart and hide him as much as possible.
Still, it's a little misleading to put his per-36 numbers next to Kyrie's and suggest their equivalent.