Not sure what a footgun is, but this approach works and has worked well for MySQL users for years. It's not about "admin functions" or anything else. It's about providing for the ability to provide distinct privileges depending on whether the user connects locally or remotely (without having to use stored procedures or have multiple users).

"In PostgreSQL if you really need to do this, I you can use security definer stored procedures which could check for arbitrary other criteria and deny permission on that basis."

You can do the same in MySQL. But, point being, you don't need to get complex to accomplish something as simple as separate privileges for the same user connecting from different hosts.