Well everyone and their mother knows Nelli is one of our few, if not only shooter on the floor and he has no problem getting shots off.
Here's the telling difference and problem for Ben. Despite whatever reasons you may come up with, his own teammates don't trust him. That comes from seeing him up close every day. They aren't looking for him. Karl's offense gives freedom to the PG's and neither are calling plays for him. As soon as Nelli walks on the floor, everyone looks for him. Why? Trust.
If you're essentially a spot up shooter who your teammates don't trust, you're not going very far. That's why I've been hoping to see Ben show more activity on the glass and on defense, and show a willingness to attack the paint, get to the rim/FT line. We've seen none of that through 2 games.