>It's sort of weird in a world that has moved to an DevOps-style ethos for most development.

The world at large makes all sorts of trends, and that by itself doesn't make them smart. As a developer, you are likely to have blind spots when it comes to quality and reliability as a result of having written the code. Even a team of developers cross-testing each other's code will not have the same ability to find flaws (before they embarrass you in front of the customer/client/user) as a dedicated tester whose job it is solely to find new (and old) ways to break things (and document them.)

DevOps is a completely different thing (though they work together with testers.)

It is only weird to have dedicated QA on your team if you don't give a fuck about releasing shit with bugs in it for the user to bump into.