Semi's D is beneficial, and Larkin has almost single-handedly won us several games already when the starters and other bench players were off.
But, yeah, I would've much preferred him to someone like Nader. With as many rookies and younger players that we already have in Tatum, Brown, Semi, Yabu, Rozier, Smart, and Larkin, I'm not sure why we couldn't spare Nader for someone like Green.