It sounds obvious when the settings are turned up really high and it's used as a pronounced, deliberately artificial effect, as in T-Pain and Kanye West and that one Cher song. Used at gentler settings, it can be almost completely transparent.
I'm willing to bet you've heard it used both ways, and on the first ones you've thought 'obvious and atrocious,' and on the others you haven't noticed it at all.
But almost every top 40 song isn't music by a musician, but entertainment (of which music is only one component) by an industry (of which the "artist" is but one small, though highly visible, part).
I don't understand why this comment and mattmaroon's are being downmodded. Perhaps music is one of the topics with which people identify too much? Like religion and politics.