That makes sense for existing infrastructure, taking waste heat from data centers and piping it through existing public systems. Especially for government environments like Denmark.

I wonder what profits would need to be for a private energy company to install additional equipment at a remote fracking site to capture the burn off energy to then sell to a data center to then use.

The problem is finding a well-located user of the waste heat. Homes and offices are great in colder countries. Some industry can use it, but the examples I can think of (food/drink, heat for drying paint, making paper, some chemical/drug processes) aren't usually sited in the middle of nowhere.