Nice post Vadim. I totally agree that not everyone can program midi files, that's why there are so many bad ones on the net and available to buy from companies who seem to push out any trash just to get rich.
I enjoy doing backing tracks for singers and groups on my PC and have done now for the past 17 years. Many singers can't play an instrument so they need good quality backing to bring their performances to life. I've been in bands, played on the organ circuit since I was 11 until 17 and I'm now a solo keyboard player, however I don't use any of my own backing tracks (not midi tracks, these are recorded as real audio files with real guitar parts played by me) and I would never consider using a SMF, but that's jsut me. I'd rather play 100% live and create my own interpretation of a song. I don't want to sound like any other keyboard player, I like my own style of playing so why be a carbon copy of someone else or just take the easy route out and fake to a midi entirely or just play a lead part over something pre-recorded.
Midi will always be used and if it gets people work then good, but those who have to mime entirely over the top are nothing more than a poor excuse for an artiste and will get caught out sooner or later