Yeah they're wired, larger grocery stores were kind of a problem because they need up to like 10gbps connection, which is pretty abnormal for a grocery store. Because yes, almost all of the video is processed in the cloud, although they are trying to shift more of it to processing on devices in the stores.
It's super expensive, prohibitively so for now although they might actually bring down the cost. But they're allegedly finding that sales are actually higher in their in-stadium stores compared with the alternative, so it might actually have a legitimate advantage there. Plus they mostly sell overpriced beer there, so it's not totally crazy that it could be profitable.