Michael,
Try flymowing 210 bunkers, by the time you finish 18, you mine as well go back to #1. I used to despise grass face bunkers, but my taste has evolved a bit, they have their place, but I know they are a pain in the ass to maintain, and dangerous. I said what I did because I don't know how else you can mow the "inside" edges on some of these newer "frilly edged bunkers" places like Erin Hills or Chambers bay.....etc... maybe you can do it with a weed wacker?
When we built the bunkers at Rock creek with Tom's crew, we made sure the edges near the fairway were less intricate, smoother, and easier to mow, ideally able to cut with a fairway unit. In my opinion, that's the way it should be. And the difference of making "natural" frill edged bunkers hassle free or a total pain in the ass which presents un-playable situations out of near misses.