In addition to the "dark space" issue, I wonder if the bigger motivator for this kind of equipment is the issues with loading reels in the dark. I have stainless steel reels that I have tried to make work and I have ruined more rolls than I have successfully developed with them. I eventually gave up and bought a Patterson tank, but I couldn't load that with any reliability either. I replaced the Patterson reels with some that Freestyle sells that have a wider slot to guide the film in, and I get pretty decent reliability with those, but it still f's up with some regularity, and I have to figure out a way to unspool half the roll in complete darkness to start over, which is quite difficult because separating the halves with film half loaded mangles up the film pretty significantly. I know that I am more clumsy than the average person, and plenty of people have no issues with stainless or Patterson, but I'm not the only person that has these issues.
All that said I have found the perfect system that I can always load in the dark--the Kodacraft aprons. But they aren't sold any more. I don't really have an interest in these lab-box type system, but people that have been home processing for 20 years may have forgotten how much anxiety there can be loading those reels when you're new to it.