Same goes for when people say, "Oh, I'm so bipolar!" when they're not and they're using those terms improperly to mean something entirely different. Having bipolar disorder is NOT a walk in the park or to be taken lightly. It is a serious mental health condition.
And yes, it DOES matter. Especially to people who DO have those serious conditions, which are infinitely more severe than your predilection for having things 'just so.' It also matters to the people who love others who have those mental health conditions.
When you know people – as I do – who have obsessive-compulsive disorder or bipolar disorder, you realize how insulting it is for others to use the terms or acronyms in jest when what they're referring to is NOT actual OCD. They are, instead, perfectionists and/or neat freaks.
Proper terminology matters. Most people who suffer from OCD don't think it's cute or funny at all. It can be disruptive and makes life hellish for them, sometimes driving them to suicide.