Yup, I used it on a client application the first time I used it and it worked very well. The project was finished a while ago, and Nativescript has made leaps and bounds in that time, it's even better today.
I used Nativescript-Vue[0] which has since been brought under the nativescript umbrella fully, and it was a great experience. Vue is drastically less complex than React and that translated to very easy app building.
I don't build mobile apps (I think the market is somewhat saturated), but if I had to, I wouldn't even consider Flutter these days (I've built a small app in that as well), or building natively (who wants to be an "android developer" these days if you don't want to specialize in it?) -- Nativescript all the way.
There's also stuff like svelte-native[1] -- Nativescript is a better platform to build on than React Native. Props to the React Native team for being the first to have the idea (same goes with the component-driven design of react itself, though arguably backbone/marionette views were first), but Nativescript is a much more flexible and easy to use solution.
You can[0] -- that's one of the upsides to the web as a platform, you get to use some familiar tools to debug the JS side of things.
Also, I'd honestly argue at you that development is so fast for Nativescript (especially when you start using Hot Module Replacement[1]) that you could get away with print debugging.
And again, another really awesome thing is that nativescript integrates really well with native code -- you can write your game/native-feature-heavy screen in native java/kotlin/swift/objc and just write every other screen with nativescript. Flutter makes that just a smidge harder to do because of how it integrates (drawing every pixel) -- it's possible[2], but my money is on Nativescript being better at it.
