Using "WebView" doesn't just mean performance issues. It's a matter of choosing the very stack itself. You're starting out with browser as your base. There are many things that come with that decision.

Also that Bitcoin app is a bad example because it's a very simple app.

To be clear, I have programmed in both native ios, ionic and native android. I'm primarily a iOS developer so had no idea how Android worked when I first tried building an android app, so when I first tried my "cross platform" app on an android phone I was shocked to find out there are so many details that make it feel NOT native. iOS and Android have very different UI and you need to build for those experiences if you want to really optimize for user experience. It's not just a matter of performance. That's why I learned java to build natively.

Lastly, in this and age, why not just learn react native instead of boasting about how still using web browser is good enough? You really have no excuse here if your reasoning is that you want to use web technology to build native apps.