[int_19h]

From the article:

"Is TWA a Hybrid framework, similar to Cordova?

No. With Cordova or other hybrid solutions, you are typically shipping your web resources (HTML, JS, CSS, etc.) within your APK package. Also, the engine is different and isolated from the users’ browser, so no session or cache sharing.

With Trusted Web Activity you don’t need to package any resource file from your PWA (only native components, in case you want them); all your resources will be downloaded and updated on the fly from your Service Worker. Your PWA will still be rendered with the installed Chrome version, sharing all storage, cache, and sessions with the browser. Therefore, if your user has a session on your website opened when the user installs the app from the Play Store, she will still be logged in. The user is just installing a shortcut to Chrome using a special mode."

[pier25]

So what's the point of the APK?

[UncleMeat]

The OS needs an APK to run it. Just opening your page in the browser won't let you customize as much.

[int_19h]

To contain the metadata for the store entry?