I can only speak about Germany, where as far as I've seen (and I haven't seen many) they definitely use styles and (sadly) third-party midi files, and often they sing. To what degree they even use MP3 I don't know. But even if it were the vast majority it wouldn't change a bit of my opinion. Unless they use MP3 during "club disco" times during the evening in the role of a DJ, moving away from their keyboard and clearly showing that they stopped playing themselves - that's something else.