I've lived in Phoenix all my life and I'm 45yrs old. Since the beginning of the bike lanes here I've always called them suicide lanes.
The reason I prefer the sidewalk for a regular and motorized bike is that I have a bit of a barrier between me and the vehicles, instead of just a painted line. It's much less stressful on the sidewalk, which makes it more fun for me since I got my bike primarily for recreation. It's also a more interesting ride, with dips and turns and occasional people to go around etc.
To each their own but I can't personally see why, if given the choice, someone would choose to run full throttle on the side of the road so close to people smashers, when there's a nice path along side it that cars aren't allowed to use, and wouldn't fit anyways. However I ride on the road in residential areas. Phoenix is not the same as other places though, so this is mostly meant for Phoenix people.