Right, they are not the same thing: they do share similarities, however. I must not have made my point clearly. My own experience has to do with starting a group that has a non-trivial operating budget (O(10k), decent for a student org), customers, technology that we developed for our projects, and funded by grants for which we are required to show demonstrable progress. There are a few groups like this at my university, so I figure it is a relatively common setup. We actually considered launching it as a for-profit business, but realized none of us had the time to get fully behind that. When I say cost of failure is 0, I mean to say you're not going to be out a substantial amount of your own investment if things go bad. And you are still working towards something you consider valuable (a degree) during the whole process, so it's not a total waste of time. But there are certainly social costs for just walking away from something you start, especially if you make a big deal out it to begin with.
I understand what you're getting at -- they are not the same thing. But I do think that some of the leadership aspects are similar, insofar as starting any organization (student, startup, community, or otherwise) requires certain common skills. If you can't/don't want to drop your studies to go do your Startup, then this might be a means to exercise a similar skill (sub)set in the meantime.
I have done something similar and I share your viewpoint, it is not a replacement for a real company in real economic circumstances but I did need to develop a lot of skills that I wouldn't have learned in classrooms.
I'm still in college though so I can't tell you how beneficial these skills will be when I either startup or enter the workforce.
I understand what you're getting at -- they are not the same thing. But I do think that some of the leadership aspects are similar, insofar as starting any organization (student, startup, community, or otherwise) requires certain common skills. If you can't/don't want to drop your studies to go do your Startup, then this might be a means to exercise a similar skill (sub)set in the meantime.