It's completely rational to think of it as a bug. The scaling is minimal and it doesn't really count as a significant visual aid.Exactly. That's the whole purpose of it. It was an intentional decision to make it bigger on the lock screen vs the home screen. Drives me crazy when people on here think it's this bug that they haven't bothered to fix in years or something.
I thought it was a bug 'till some versions if iOS 8 where i realized that they couldn't be that clueless