This was about a PHP/Symfony API and a angularjs/phonegap app. I've split it between a PHP app, Node app and a phonegap app previously as well and it felt like a nice workflow and I felt like I was getting more done. You're right it might not be ideal for everything. But for new comers I think it's a solid place to start. Especially for PHP, which can get a bit messy!
Never really work on PHP before, but I think you should include those info so people like me will understand this setup is optimize for which language.