Easy Debian isn't a bootable "full" OS. You still boot into Maemo for that. It allows you to do one of two things, run Debian applications in a manner that makes it "appear" seamless to Maemo.. and/or simply start another X session (using like LXDE, or Gnome, etc) over the top of maemo.. and giving you the ability to swap from one to the other.

IIRC, it's a tad slower than booting into Debian/Mer, but it's quite a bit more user friendly.. and you retain the battery life of the Tablet as opposed to Mer/Deblet, where battery life plummets when you boot into it.