Android-Kotlin-Clean-Architecture

To enable Google to crawl your app content and allow users to enter your app from search results, you must add intent filters for the relevant activities in your app manifest. These intent filters allow deep linking to the content in any of your activities. For example, the user might click on a deep link to view a page within a shopping app that describes a product offering that the user is searching for.

this is the first reason and the second one is

ACTION_VIEW Use this action in an intent with startActivity() when you have some information that an activity can show to the user, such as a photo to view in a gallery app, or an address to view in a map app.

while The ACTION_MAIN action indicates this is the main entry point and does not expect any intent data. so activity can have both