China's already doing this with nuclear, so there's a good chance they might do this with data centers too. https://www.world-nuclear-news.org/articles/chinas-first-commercial-nuclear-district-heating-scheme-expands

The fact of the matter is that air is an incredibly inefficient thermal conductor so data centers have to burn a massive amount of extra electricity just to run powerful fans and chillers to force that heat away. That extra energy consumption means an air cooled facility is responsible for generating significantly more total heat for the planet than a liquid cooled one.

When you put servers in the ocean you utilize the natural thermal conductivity of water which is about 24 times higher than air and allows you to strip out the active cooling infrastructure entirely. You end up with a system that puts far less total energy into the environment because you aren't wasting power fighting thermodynamics. Even though the ocean holds that heat longer the volume of water is so vast that the local temperature impact dissipates to nothing within a few meters of the vessel.