I built an app like that. It uses a WebView, although all the HTML is self-contained and it only accesses the internet to make API calls.
Mobile app development really sucks, as a developer. The frameworks, the build tools, the specialised languages that can't be used anywhere else - it's a hot mess. Making an 'app' using that method is much quicker and easier for me because I get to use HTML, CSS and JavaScript, which I already know and have the tools for.