Really? When it’s not you but a tech illiterate computer ‘newbie’, you don’t see any benefit to a popup warning them that “programs downloaded from the internet could be dangerous”?
Didn't we go through this with Vista? The average tech illiterate user only ends up trained to ignore and continue. You might as well drop a few hundred knives labeled "warning sharp" in the middle of a playground.
It's reasonable to have guessed that there'd be a benefit before it was implemented, but now that we actually have such a popup, it's clear that there's not, because the newbies all ignore its warning and run the malware anyway.