If we already had role players who could score then I would agree with you, but because we don't, Vaughn's roster spot denies a young scorer a place on the team.
Vaughn isn't a scorer and no one is expecting for that to be his role, but because we desperately need scoring, he isn't really helping to fix our weakness, if anything he is holding us back in some ways, even though he plays admirably and to the best of his abilities. This isn't about slamming Vaughn but assessing the needs of the team.
"Filling a role" and "not making mistakes" is great when we have a super talented deep bench but right now too many of the players on the team are complementary role players who only do all the "little things." Is it wrong to say that we need players who can do BIG things, like score the basketball?
Under Pop, and with Tim as our leader, a strong defense will not be our weakness. I believe the FO admits that scoring points is an issue for this team. And Pop, in my opinion, is not as strong on the offensive side as on the defensive side of the game. How else to explain infatuations with shooters who can't shoot like NVE and now Tolliver?
So yeah, I think Farmer could help the team more than Vaughn.