So instead of going to the UPS offices to pick up the package for free, I instead go to one of these for a fee. I don't see the advantage, there are UPS locations everywhere and are easy enough to get to.
This just seems like an ugly solution to a not real problem, and with a WebVan like costly infrastructure before it's even remotely useful. There has to be enough of these ugly green boxes to be more convenient than the just going to the shipping depot, the cost to get to that point seems prohibitively high, after any significant number of boxes they will become targets for theft and vandalism too, another operations cost to deal with. Webvan revisited.
You must not live in Canada, or any place that isn't super urban. Also, not everyone has a car. I can imagine myself using this if I lived in a dorm, especially far away from home (speaking out of experience).
On theft an vandalism, from what I see in their current installations, they're installed in busy areas inside train stations and school buildings. That's a lot better than hiding things under your door mat or tossing things over backyard fence.
There is also the receipt of packages while away on vacation, etc. Certainly not a huge market, but I don't think its fair to say this isn't a "real" problem.