Comment you replied to was talking about automatic updates, not installing apps. Google Play and vendor installed apps can automatically update apps in the back

Comment you replied to was talking about automatic updates, not installing apps. Google Play and vendor installed apps can automatically update apps in the background without needing to prompt the user for permission to install each individual update, while a typical f-droid install requires the user to click through each update and press “install” at the prompt. This can be fixed by making f-droid a system app, which requires root or an unlocked bootloader.