Cross platform traditional apps when you have at least one poor soul who is willing to work with the Android NDK/JNI: shared C++ business logic + minimal platform-specific language for UI.
My view is that unless your app is trivial (say, less than 10K lines of code), it's never worthwhile to re-write the entire app for each platform. Share as much logic as you can with the "common" tongue, C++.
Performance is pretty good, and the UI is entirely native Android.
But if you're only targeting Android and iOS, you'll likely get to market faster with something like React Native while still retaining native UIs. It'll certainly be better than Phonegap/Cordova/Ionic.
I'm also not sure how hard Qt actually tries to give you UI components that look like what you would find in a typical app. If you have Qt experience then I'm sure you can make it work, I've heard good things from people who have used it.
I'm also guessing it has much more consistent and robust UI behavior compared to running things in a web view.
You'll have to find someone who has actually used it though to get a real opinion, I'm just speculating here.