I'm sure this expression and others that are like it have lots of use in various spoken expressions. But as the same idea can be expressed differently, why bother?
Long expressions have many functions in any language. They give the speaker time to think, they can act as "padding", they can make an expression more tentative and so more polite. They can use simpler words. That's why you get lots of long expressions and unnecessary words in spoken English.
So there's no rule that one always uses the shortest expression.
But in this case, the extra words don't help. They aren't padding, like "Well...", they don't add any politeness, and they don't simplify the vocabulary. There is an easy way to avoid them, and given the chance most speakers will use easy language when speaking.
So not because it is shorter, but because it is easier.