I'm having a hard time finding a good, comprehensive comparison between Qt and Electron. My current understanding (which is probably wrong) is that Qt isn't much smaller than Electron itself and I would need to use C++. The animations do not look simple or easy to understand at all, but that's just a first glance.

QtQuick, at first glance, is weird. It uses JS and the animation transitions look pretty close to css transitions.

I guess what I'm looking for here is: how is it a clear win over electron other than just raw speed?

Maybe I'll make a non-simple app in both electron and QtQuick and see how they compare in terms of ease of development, development speed, app size, ram usage and "speed".

You don't need C++ with QML.

https://github.com/qmlnet/qmlnet

I used it at work on my embedded devices.

https://medxchange.com/4klear-all-in-one-camera-recorder/

I highly recommend it. PS: I'm the author.