I would imagine you would still need tethering support from the carrier... In iOS 7, there's the button to set up a hotspot, but if your plan doesn't support it, it was just say to contact your carrier. I imagine the new feature just eliminates the steps of going into Settings on your iPhone, but that a supportive plan is still required.
Isn't that what Photostream was originally for? When it was first released, it was so that photos taken on your iPhone would automatically sync to your Mac, with the most recent 1,000 photos remaining on your iPhone. Clearly, more people want all photos to live in the cloud and to have access to all photos on all their devices.
Why would this bother you if it goes directly to an online service? It is likely routed through Apple's servers and is anonymized before sending it to Wikipedia, etc. Or are you concerned about the data going to Apple?