EDIT: formatting Almost everyone here talks about abandonment. It's become a sad Google reality, but I'd hazard that some people are posting from Google Chrome, which would defeat the point about worrying. I use Flutter, I've released an app that's been in prod for about 5 months now. Flutter runs on Dart, which is a Google-bred language. From my little knowledge, most/some of the people working on Dart are the team…
Cross-platform frameworks always seem attractive because you can write code once and run it on both Android and iOS. When you start development it might also feel productive at first because you finish 80% of the project much faster than with using native platform frameworks. Problems begin when you need to interface with native code or if there are some small annoying issues. You get stuck for hours and days trying to solve something that would take much less if you dealt with native platform SDK. In the end you are not completely satisfied with your hacky solution and it took as much time as native app would take.
My opinion is that if you have a very simple app, it might be OK to write it in, for example, React Native of Flutter. But if you have a more complicated app and it's an important part of your business, you should go native.