The fact that everyone does it doesn’t mean it’s not a big deal.
It’s done for legitimate purposes, for example knowing which apps to launch for a given ‘Intent’ or checking for the existence of Google Chrome to attempt to launch a Chrome Custom Tab.
It’s normal functionality for mobile apps.
Now, if they are scanning visible installed packages and sending that data to their own servers for storage, that would be a story, but there’s no evidence that that is occurring.
By the way, love your username.
Isn't the whole point of 'intents' exactly that apps don't need to know what other programs are installed, delegating the decision to the OS and user?
Explicit Intents are also common and are used for a variety of purposes.