Indeed, it's much more comfortable to code on my desktop computer, and that's what I do as much as I can.
But working on a smartphone as the advantage to let me work from anywhere, whenever I have a little bit time to spend (and able to concentrate). Since I can work on this project only beside my full-time job and another hobby project, it's still really good for me I can spend around 2 hours everyday on it, even in a not so ideal dev environment. The question is between doing it this way, or not at all.
Also I have been working this way for a while on other game prototypes, and now I don't feel so much struggle anyway.
I guess it's also about habit to be able to work on small screen, and to learn fast-typing with a virtual keyboard ^^
And you should try AndroidIDE. The UI is quite well done, and refactoring or auto-completion features help a lot.