Support tooling for web UI development is superb. I don't know the state of the art in Java/JVM GUI, but the rapid prototyping you can achieve with live code r

Support tooling for web UI development is superb. I don't know the state of the art in Java/JVM GUI, but the rapid prototyping you can achieve with live code reloading, browser DOM inspectors, etc. is unmatched in my (admittedly limited) experience with UI toolkits. QtQuick is the only other that's come close for me, and it's heavily inspired by the front-end web "toolkit". It's probably more about the developer experience than anything else. Bundling Electron in every application is pretty bloaty.