So the stack is CPU, heat spreader, array of these products? It'd be nice if the datasheet showed performance curves across temperature and pressure as well.

The examples I've seen don't use a heat spreader, interestingly. A video demo had the CEO saying they depend on the velocity of the air to remove the heat quickly, so no heatsink required.

It’s a bit confusing but from a YT video it seems the device still need a coldplate + heatpipe, and the airjet is stuck on the heatpipes themselves replacing cooling fins. The airjet itself blasts the air into it’s own internal coldplate from what I understand.

That is correct - in response to the question about whether heatpipes could be removed, the CEO mentioned that their requirement is uniform distribution of heat on the copper plating on the airjet and putting it on the heatpipe helps achieve that so their plan is to stick it on the heatpipes.

That makes a lot more sense to better handle fluctuations in load.