More props to them for clearly knowing it has its limitations and downsides... I'd pick a developer who used a language they knew inside and out and were informed and aware of the downsides of the language over a zealot who thinks their language of choice works best in every situation (my most common experience of these types are in the ruby community, by a quirk of coincidence).
PHP was the language I used to teach myself how to develop for the server-side when I'd been purely a front end dev many years ago and I still like it (though granted I like Scala more) because it's always felt like a language you can sit down and get shit done with quickly and without fuss, and sometimes that is as important as any other attribute you can attach to any other language choice.
I'm not too lazy to learn anything else, I always use the tool that is best for the job at the time. Recently I had to design a web application that outputs MS Word .DOC files in binary form. There's SHIT support for this in PHP, so I wrote the whole web-app in Java, because Java was the right choice given the task at hand and the clients existing platform.
PHP is the right choice when I want to get something done quickly ... I can hack a website together in PHP faster than any other language, but it will be exactly that, a hack. PHP's strength is speed of development, and low barrier to entry means lots of developers out there who can help. (High supply of developers also pushes cost down, another bonus for me)