OK! That's news to me, I must go back to the v16 (?) release notes and learn more about this.
Both inherit and set capabilities are now individually controlled permissions related to membership.
Hmmm, what drove this change? (I guess I'm getting back to the rationale from earlier).
The previous model was not granular enough?
And the new one is as granular as it gets?
Essentially yes. Inherit used to be a property of a role and not a specific membership which was deemed undesirable. We were fixing up the broken CREATEROLE attribute and felt these improvements were needed as well. Once inherit became optional per-membership it made sense to treat set the same way.