I'ld have to say that it depends on how it is used, contextually.
Kind of like the difference between "functional nudity" and "more people will want to watch it cause Megan Fox goes naked".
I don't mind functional profanity at all. In fact, I miss it if it isn't there. To the point even were I usually lose interest in the film or series. Because at that point, I feel it loses credibility.
For example, if we have a scene with a stereotypical "couple of brothers in da hood", it just wouldn't be credible acting if they didn't use the f-word every other sentence. It just isn't right, contextually, if they would use goodie-goodie english.
In the real world, they use dialects, slang, etc.
I just get bored, and irritated, watching films where "common folk" use "school language".