I do not doubt the statements that Adminer/Sequel Pro or others could "do the same thing" or even "do it better" than phpMyAdmin, but phpMyAdmin is what everyone knows how to use because it's everywhere. There's even a direct link to access phpMyAdmin via the WP Engine dashboard, so using Adminer on Local makes for an inconsistent workflow across your own corporate platforms. That's the part that bugs me the most.

phpMyAdmin is practically muscle memory for the basic operations I need to accomplish. Every time I open Adminer I fumble around and struggle to figure out the basics of how to use it. It's like the funky dials and joystick gear shifters they're putting in cars now. Literally everyone already knew how to use the PRND lever, it worked fine. Having to relearn a basic operation, without any real "payoff" is the issue with using Adminer.

What does phpMyAdmin do that Adminer doesn't? Legit curious. They are both ugly tools :)

Yes 100%! It's a default tool, used by most web hosting platforms out there. Ugly or not, devs are used to it. No one has heard of Adminer. Don't try to change something if it's not broken..