More like binding to C++ is difficult, lack of free non-copyleft implementations, and general lack of advantages over Flutter/Electron. After all, Embarcadero Delphi is also very powerful and easy to use but nobody uses them for good reasons.
qml is by far the best way to create frontends. its just so good.
What makes QML so good?
good question. i think its precisely the right mix of declarative UI definition and enough freedom for.procedural js