I think it's a complete waste of time. I won't say effort because it honestly doesn't sound like much effort was put into any of those songs or videos. Granted in the rappers defense, they feel they're spittin' hard and really feeling themselves, but fact of the matter is... at the end of it all, it sounds like bad karaoke.
I don't see the promotion part of it anymore. Maybe if it was 2002 - 2003 perhaps, but it's bad enough the rap game is at a stance. Too many mixtapes. Stores are selling mixtapes now like WTF? A mixtape was made for promotion purposes and handed out for free. And now rappers are making videos to it? SMH
Back in the day mixtapes were handed out by DJ's and the rappers would spit a freestyle over the break beats etc. That's all the effort that was put into them. Now a days, rappers are making full albums of mixtapes.
Ever since rappers like 50 Cent (love him or hate him), blew up off the mixtape circuit everybody has jumped on that bandwagon hoping to be discovered. They can deny it all they want, but that's what it is.
Instead of stepping up their bars on a used / popular beat, perhaps all rappers should step it up in every aspect. Meaning original beats and bring a dope album & stop wasting time on mixtapes altogether.