I haven't seen the show since it opened in 2019, so unfortunately I can't name specific examples. But I distinctly remember feeling as though Chavkin made great use of the revolve and the elevator as tools to physically represent character relationships: distance, turbulence, and other dynamics that existed in the plot were heightened by the use of physical space, without feeling excessively literal.
That said, at the end of the day these are directorial choices. Like any director, she's using a set of tools to mold, craft, and otherwise convey the story with a sense of clarity and intention. But another director might've found different ways of doing those things, that don't require a revolve or a lift. In fact, when Chavkin herself directed the show Off-Broadway, it didn't have either of those things, and I'm sure future directors will tell this story without those scenic elements too.
So like, are they important? Yeah, for sure. Are they ESSENTIAL? I'd say no.