PGP is better for those config/standardisation reasons, but Bitcoin's cryptography is arguably more secure. Awkward situation.
I'm sorry I still don't see how keeping your PGP over the years is easier/more convenient than storing a legacy btc addy for that purpose.
I get that some people will already have a PGP and this will come at no extra cost/complexity, but then again, I highly doubt most people on this forum are using PGP. However MOST of them do own/still have access to their old legacy addresses.
While your proposal would be a nice to have I don't see any point or reason in forcing people into it.
So the solution is already here. If you are more confident in keeping your PGP, you are already welcome to stake it. If you like BTC legacy more, stick with that.
To me this really is a no brainer.