It's one of those rule misconceptions that becomes so ubiquitous that it starts being treated as real. Or maybe people just like opportunities to roleplay criticals.
While I don't actually think DCs need to be universal, there shouldn't be any critical success or fails.
In combat, because it takes place over such a short period of time and because it's outcomes aren't managed it makes some more sense.
Here's an interesting article on skill checks I like
thealexandrian
