There's quite a few more deserving relievers than Betances. Osuna certainly being one of them, I'm surprised with his save totals that he wasn't included on the roster. Chris Devenski is the other very notable omission.
I still can't believe Ervin Santana made the roster.
Considering Tepera was a pretty bad MLB pitcher with alright MiLB numbers and Barnes dominated the minors, I would assume the latter had a better projection easily, and is likely to project better going forward.