Bring on the exploding drone boats.

[1] https://sealandgov.org/

https://www.cnn.com/travel/article/pangeos-terayacht-turtle/

TL;DR: Pangeos was a concept for a floating free city that trended a few years back, but was never built for obvious reasons, just like how these floating data centres will never be built. Presumably some people were bilked into paying money to the Pangeos scammers, just like there will be those who "invest" in this.

The problem is that it costs a lot more to put a nuclear reactor into a permanently sea-worthy form-factor than it does to build on land and put up with some pesky taxes. There are plenty of places with lax regulations (environmental and otherwise) that will be happy to let you build whatever size data centre you want if you're willing to build the power generation too.

Have these guys factored in the cost of a task force of protective missile frigates, subs, and destroyers at each site?

I’d be stunned if anyone takes this seriously

The sensible way would be to use the waste heat for district heating, but let's heat the fish instead

The fact you're surrounded by coolant, can use intrinsically safe versions of high pressure reactors and have low latency between multiple markets with one datacenter is also a big plus.

That you're not competing with humans for electricity or water is another.

That said you'd want to build a semi submersible platform with the nuclear reactors in the pontoons and the superstructure able to house container based datacenter units. The only place with enough exoretice to build these is South Korea which isn't a deal breaker perse, but Samsung can pretty much eat your lunch if these get successful.