Videographers, mostly. DSLRs can't autofocus worth a damn during live video, so people would rather get the nice MF lenses. I'd know, I use my film lenses for video when they're not being used for film. You wouldn't believe how many (digital) canon people own a whole collection of Nikon MF lenses.
I'm one of these people. I actually have more Nikon MF lenses than I do Canon EOS lenses. They really are better. I acquired them through a more traditional method, purchasing them for my Nikkormat and Nikon FG and I got the idea to get an adapter on eBay and see what they do on my Canon 5D Mark I digital, which uses a full-frame sensor the same size as a 35mm negative. The 105/2.5 is a fantastic portrait lens, I use a 50 1.4 for LOLbokeh shots and was using a 28 f3.5 for landscapes for a while.
They see more time on my Nikkormat but periodically I adapt them to my Canons and kick it old school for a day.