You don't need to have all apps installed. For example: you can go to facebook web page and launch an instant app, so you have the native experience without having the app installed. Also with places like amazon or anything that you don't use very frequently. Moreover you can test an app without installing it.
that you don't have to install apps to use them? Like you go to a web page and can have native experience, with its animations and everything. Much better than a web experience.
