I personally use PHP all the time, I love it. I can code large, maintainable and secure applications with far more speed than any other language I've ever used ( and trust me I've used a lot ). It's my language of choice when I'm building web applications.
Not only is it available everywhere! but it's been established for long enough that there are a wide range of top quality frameworks and libraries written for it. Oh and these have been written by developers who I'm certain are much smarter than us both.
And why the hell is mobile development any harder than web development. It's just code, not arcane magic. Trust me I've seen, and will continue to see, just as much badly written/badly performing code for mobile applications as I do for web based ones. Just because you're using Objective C / Java as the tool of choice doesn't make you any better or smarter a developer.
If there is a mobile offering coming up based around PHP, I'm looking forward to trying it. If it allows me the same benefits as the language does on the web then I'll be using it, regardless of how many people think that makes me "not smart".