I've done the same thing with a todo app.

I find that a convenient UI becomes the most important aspect of some applications (to-do list, alarm clocks etc). Getting it to be exactly the way I like it is a benefit by itself.

I've been thinking of making a note taking app for my phone as well. The 10 or so that I've used all have had issues that made me not like them for one reason or another. Eg 16k char limit per note, no searching inside a note, broken bullet lists, long startup time etc.

With millions of todo apps released daily, it boils down to marketing which have a taste component.