I don't see how it matters whether it's sustainable or not, or even if it can be replicated in MLB. That OPS still isn't going to get him to the majors, especially with the OBP.
By all means, I hope he has a second half that changes the conversation. One of several things that jumped out at me in that Athletic article is a reminder that all teams put a "prospect" or "non-prospect" grade on players in other systems. They were talking about Gowdy, but it would be interesting to wonder how many teams rate Moniak, and where.
Evaluators from other teams are divided on Gowdy, 23, but there is a consensus that he has at least regained some prospect shine. His fastball has reached 97 mph. It sits 94 to 96 mph. He’s shown an above-average changeup, in the evaluation of two rival scouts, with a slider that needs refinement. Not all are convinced: At least two teams have resisted putting a prospect grade back on Gowdy. He is, nonetheless, more interesting now.