Larnach and Wallner are examples of how a small-budget team needs to operate. They aren't identical players but to a great extent fill the same role on a roster. Both still have minor league options. So in principle, they are a good use of the 40-man roster, and whichever one is performing better is the one who should be on the 26-man. If by some chance both are performing great, the manager will figure out how they coexist (Wallner in right, Larnach in left). But for a team that's not rebuilding, and not willing to simply discard overpaid vets and let the youth take over by default, it's a nice combination to have. (Whether the player consigned to AAA and putting up great numbers is going to be happy, that's a different problem that management has to factor in.)
I wish they had more of this kind of roster flexibility, instead of veterans like Farmer and Margot who suddenly got old. (And I realize Manny doesn't turn 30 until September, but he's playing old.)