I see it differently. The choices they have for the last roster spot is mainly players who kinda suck. They could either
a) fill the last spots with veterans who suck but benching them doesn't hurt their development
b) fill the last spots with rookies who suck, benching them DOES hurt their development
Option b also burns service time, so you get less time from those players in later seasons when they're actually good.
I am not bothered at all that Mickey Gasper, Dashawn Keirsey and Ryan Fitzgerald are taking up spots on the MLB bench while Aaron Sabato, Emmanuel Rodriguez and Payton Eeles play every day in St. Paul. Sabato, Rodriguez and Eeles are sufficiently challenged at that level.