Counts your keypresses per session (the one and only real statistic you need) and shows a chart. Simply always start this together with osu!. The two keys are saved in save.conf and the data is saved in stats.json.
First time Electron, it's definitely fun and very easy, but it's too overkill for small projects like this (over 100mb with Electron would be like a few mb with a WPF application in this case).