I think "promises" is the key word there. Data centre's want power, as you say, but they want it now, not 15 years from now.

So yes, when SMR's are "off the shelf" (aka from "order" to producing) , including permitting, construction etc, within a couple years then they are appealing.

I don't think we're quite there yet.

Sure. But this is why what Microsoft did here was just a hedge. It did not cost them much (if anything at all) to become a member of the World Nuclear Association. If the SMRs become reality a few years down the road, and if the demand for datacenters increases significantly because of the increased use of LLMs, then they stand to benefit a lot. If either of this does not pan out, then what's the risk for Microsoft?