It saves making three separate macro slots for the exact same button. See Raise Macros. Individual button count per class hotbars isn't affected, but it's still bloat. And Warden's Paean can save the need for all three anyways. I literally did that so our SCH could take Protect in that slot and still handle the ghost in O5S prog. And it at least warrants a different treatment because it's functionally different from the other 'Cleanse' effects, even if the mechanical output is the same.
Call me jaded but given the Dev team's track record I expect nothing to happen regarding macros at all in the next 5 years. We'll be lucky if we see more shifts towards active mitigation for tanks and some proper healer rebalancing in Shadowbringers. The button consolidation is all but mandatory now sure, but I could see them adding more buttons still because there is room for it still. I wouldn't be opposed to what Kalise proposed, specifically the bit where Swiftcast is added to every caster's class list instead. That would be fine, so long as it was treated at least similarly to Disciple of Hand actions and kept the same name and similar base animations/particles on each class. That's where the mandatory stuff would go, and the Role Actions Tab would be renamed to Situational Actions. However, I do not see them splitting actions up again by name without some major kit reworks to justify it. There simply isn't a good reason for them to keep similar baseline actions split if they can afford to keep them together. The only reason I think the Mandatory/Situational Role Action split would happen is because they're more likely to keep everything on that tab. We still have Eye For An Eye and Peloton despite both being long overdue for removal (not that E4E isn't good, but RNG is still RNG). Break exists purely because of one savage fight it saw use in.
I agree, they're going to have to trim something, my hope is they give everyone access to all CC and party/ally mitigation utilities and go back to 3-5 slots for Role Actions so every comp can have access to that situational stuff in general. But in terms of the abilities that each role actually needs? That I expect to be kept as close to the way it is now as possible.