I can't imagine trying to write complex code on a phone. Heck, I can't even imagine trying to write an article, or anything much longer than a tweet on those tiny phone screens.
I would like a PC without fan noise, though.
I bought a Galaxy tablet for reading books, because it is nearly paper-sized, had an HD display, and is completely silent. It's marvelous for that, and I'm very pleased with it. But it's still too small to program on, both the display size and the inadequate storage.
That makes sense and I'm in a similar situation right now. However, going forward, monitors and desktop computers will become increasingly redundant with the smart tvs and phones that most consumers will already own.