In the past few years the robo-voice was overused so there was some homogeneity to the vocal sound, although the actual music was still different. Now, that robo-voice is not as popular. As you mention, Autotune's main use is not so much as a creative tool, but as a way to fix problems. Most of the time this is simply to fix otherwise good takes without having to redo them over and over again. The idea is to make edits that are not noticable or as they say "the best edit you can't hear". Simple intro to the plugin here: http://vimeo.com/91670669