The new app model does not require an installation process for an app or parts of it to work and has multiple potential uses.
Google Play Store Instant Apps Feature Now Lets You Try Android, play games download
Google Play Instant Apps & Games Not Working? Check These Settings « Android :: Gadget Hacks
The Google Play Store will now let users try apps before they buy them
Android Instant apps - what do they mean for users and developers?
Google is rolling out a Try Now button to test instant apps on the Play Store - news, now play
The Play Store gets a “try now” button for games, no install required
Play Store Console: You can't edit this app until you create a new app release declaring sensitive permissions : r/androiddev
Gaana launches instant app on Google Play
Google Expands App-Testing Requirements for Android Developers
In-app updates Android Developers