Hi. We have a required update for listing application
>>> Your app is currently using ScriptTag API. Update your app to theme app extensions to ensure compatibility with Online Store 2.0 themes. Refer to this help doc for more context. See this screenshot for details.
I understand that migrating to App extensions is required because it came with some advantaged and improvements. For example, when you use App extension you dont have to worry about uninstalling the app because it automtically removes all the code that you add to the theme. In the past, when you used script tag it was a problem because once the merchant uninstalled the app, you access token was not valid any more to remove the changed you'd made.