I personally don't find PHP attractive at all, but in recent months I've been very surprised to meet some devs who are making absolute bank with it (including WordPress devs). I think success as a freelancer depends a lot on being a good salesman, delivering value to your client, and being efficient. Whether the end product (eg, a WP installation) is "quality" in terms of software engineering might be highly debatable... I can totally understand why a Scala dev wouldn't want to touch PHP projects with a 10-meter pole, but that doesn't mean that you can't be highly successful with it.
Personally, I can code in a few languages but I build mostly in JS. I understand why some engineers would not want to work with it and I'm not personally offended by that, but I think ES6+ can provide a great dev experience. And while there's certainly a lot of crappy jobs in the space, there also seems to be really interesting work to be found around Node / React / Vue etc.
WP is such a dumpster fire it's unlikely that PHP skills are going to become obsolete any time soon.
From a freelance/consultancy niche it's almost ideal. Demand is high, and employers/clients are likely to have relatively simple requirements (i.e. a brochure/catalog site with a bit of a backend, not a huge industrial db that needs to run at planetary scale backed by a devops machine.)
It's not a personal interest but it seems to work well for people who can stand out from the pack, even a little.
Personally, I can code in a few languages but I build mostly in JS. I understand why some engineers would not want to work with it and I'm not personally offended by that, but I think ES6+ can provide a great dev experience. And while there's certainly a lot of crappy jobs in the space, there also seems to be really interesting work to be found around Node / React / Vue etc.