The reason is to protect the innocent, of course, they're mostly clueless about security! But I don't know the level of practical benefits for this measure, sup

The reason is to protect the innocent, of course, they're mostly clueless about security! But I don't know the level of practical benefits for this measure, superficially seems to be rather low, but then (assuming silly usability issues like "appears frozen" are fixed) what's the downside?