This doesn't seem to actually be a mesh network.
You can connect to their "supernodes" which are the backbone, that connect to the Internet proper. You can also connect via other member nodes. So by my understanding of the colloquial term "mesh" for wifi, it is.
I do take issue with their FAQ stating they're not an ISP. They are providing Internet access to the public. They are an ISP, even if their structure and methods are unconventional. Maybe they're avoiding the term due to legalese?
It's an interesting project. I wonder if something like that would work in urban San Antonio... Hm!