What is the advantage of making f-droid a system app?

F-droid (0.7) has two options:

One to grant it "root" powers, and another to give it "system-app" powers.

Just using it as a "root" app will let it install apps without going through the whole "Are you sure you want to install this app" page.

What does System-app give it?

I can't test it as it crashes on my phone