An "app" on Android is not a traditional executable. It's really a library and a collection of OS hooks that execute code from that library on various events.
The home screen icon is one of those hooks but by far not the only one. If I hide it or never press it, that implies exactly nothing about whether or not code from the app gets executed while I use the phone.
The home screen icon is one of those hooks but by far not the only one. If I hide it or never press it, that implies exactly nothing about whether or not code from the app gets executed while I use the phone.