Gedit is simple and lightweight, yes, but does it have any actual advantages over Geany? You have to install a bunch of plugins just to catch up with ordinary built-in features of Geany, like code folding etc.

Whereas Geany plugins will give you extras like version control integration, optional and non-intrusive project management, jumping between function definitions and declarations, etc. And the configurable keybindings available in Geany allow you to set it up pretty much exactly how you like - though the defaults are pretty good too. Gedit can bundle a Python interpreter, but Geany bundles an entire virtual terminal.

Geany doesn't come with Ubuntu, but it's available from the repositories, it's tiny (10MB) + fast, and it provides enough features to compete with full-powered IDEs; less bells and whistles, but better support for actual text editing.