I think the problems with desalination are the cost (facilities, energy) and the leftover brine, which is damaging to the environment wherever it's dumped. It has its uses, of course, but not without drawbacks.
I've never fully understood this, shouldn't the brine be mixed in with wastewater? It's all a net-zero system, it's not like water is leaving the system.
The rest is just infrastructure (which is mostly political will).
If you are talking about using it for datacenters than that might be right, the person above is talking about farming, so they desalinate the water, the fresh water is used for crops, and the brine has to go somewhere. If you aren't really careful then dumping it back into the ocean will mess up the ocean in that area.
