Yeah, the "circular" language is obviously intended to imply unsustainability, as a system without external inputs must eventually run down. But this system is intended to have external inputs, revenue from customers that buy the services of the data centers. So the fundamental issue is just whether there will be enough such demand to justify the scale of the build-out.
These deals give Nvidia more exposure to that, in both directions. Certainly Nvidia shareholders should be cognizant of this. But nothing structurally problematic is occurring here.