Single code base for multiple platforms is not impressive these days, you can do it in many frameworks. The key thing seems to be 1. written in C++ (hence performant) and 2. Has a declarative language (QML).

1 is no longer an advantage since C++ is no longer a desirable language for UI engineers, largely because UI went from desktop to mobile and web which created an opportunity to disrupt the status quo

2 is no longer trendy either as functional programming becomes more popular. People realized they can be declarative in real programming languages and don't have to turn UI into a bunch of config files.