There flatly isn't a good reason to bring Nate Robinson into a game at this point unless it's garbage time - he doesn't pass the basketball and he couldn't guard me.
That trade was an absolute disaster.
Honestly, though, Eddie House wouldn't have been much better...Nate does the same things. Eddie was a defensive liability and couldn't pass. The trade made sense on paper.
I think what Danny didn't take into account was that Nate is kind of immature and fragile mentally. I think in NY he could score with such confidence because whether he scored 5 or 20, took 30 shots or 3 shots, his team was probably going to lose and there was no pressure on him to play defense or have a guy really trying to cover him on the other end.
When he came to Boston he landed in a situation where his actions could actually affect the outcome of the game and his teammates, his coaches, and his fans all actually cared what the outcome of each game was. That put pressure on him that he wasn't used to facing, and so he had a hard time being able to score the way he did in NY.