I don't really have any issues working out how to use modern electron apps, they all follow very simple UX patterns, I find them much easier to use than the average native wxWidgets/qt app. Simple, consistent UI is less about the color scheme and border radius being consistent and about things being simple and well laid out on a higher level.

Two apps can have different CSS while being easy to understand because the core flows and ideas are the same. While many older native apps feel like junk draw UI with crap thrown everywhere and weird app specific quirks and patterns. Even if it all does use native inputs and windows.