For us it sees plenty of use with poorly developed legacy software (e.g. Wordpress).
It seems like a really bad idea to place a web-based database tool on a public-facing host when technology exists to route MySQL through SSH.
Even shared hosts support SSH these days. If yours doesn't, maybe it's time to find another shared host!
I seem to remember installing it on my own workstation, setting up the ssh tunnel and then pointing PHPMA to localhost.
It's not my favorite tool and I've avoided it due to security concerns but I've set it up for others as described and I recall it worked fine. Like I said though it's been a while and I'm fuzzy on the details.
Workbench - Massively unstable on linux. (Although I do like the visualizing tools assuming I'm willing to put up with it crashing every hour or so).
It's doesn't have the featureset as PHPMyAdmin but it has a huge advantage in that it's a single PHP file you can upload, make the necessary changes, and then delete. If you're interested in maintaining a secure server but you don't have any better options than using a script, then it's better to upload something when you need it than trying to secure an online admin tool.
The days of painfully slow FTP servers are long gone where "it's one file" would count as advantage.
This leaves a massively worse UX and featureset.
(We are using adminer for postgresql databases, because there's no better alternative, and it makes me wish phpmyadmin supported postgres every time I have to use it.)
My favorite feature is generally the graphical database relation view. Without it i am something like 500% less effective.
The profiler (visual explain) of queries in MySQL workbench is a godsend.
Also, for general querying and table layout lookup in OSX (macOS, whatever) I recommend Sequel Pro. It has a slightly better UI when working with multiple databases (easier to switch).
So for me, at least, it's ingrained in my head that phpmyadmin is the best tool for the job given the limitations of what I've got. Although I recently switched my company's reseller hosting account to a provider that actually allows remote MySQL or SSH, so that's exciting.
Its been available at places I've worked. It was locked down by IP. The database was restricted to access by ip too, in theory making outside access more difficult.
I used it a lot (less now) and honestly, I kind of like it. The interface is a little kludgy, but it gets the job done. Queries are editable, exportable in various formats. You can construct a search via gui then edit the SQL it generates . It seems to have a lot of functionality built in, user/table management etc..
For local instances I use sequel pro too (the ssh login function it has is nice and works well).
I can't thank the people who created it and maintain it enough.
But to get the good stuff one has to configure it properly, and generally people don't bather configuring it. They just place the files in a folder.
No other web based tool for any database that i have tried even comes close.