Completely serious. Sea water cooling for data centers is already in use here in Helsinki. And water temperature in the Gulf of America doesn't seem to go above 30 C even in the summer.
Sea water would have to be piped to places like Dallas, whereas much of Finland's people/data centers are closer to the shoreline. A solution that works in certain places does not generally work everywhere.
There's no need to build them in Dallas. Just keep them near the shoreline. The only reason you have so many data centers in North Jersey is so high frequency traders can make their calls 0.02ms before their competitors on the NYSE. For an average user, the 1ms ping between Dallas and Corpus Christi is not a problem.
We have a home in Houston. Over by the big gates down Sunset.
I have no particular objection to building datacenters there.
All that said, I think you're being real hand-wave-y here. The climate in Houston is materially different than it is in Dallas. So there's likely a reason these companies have been locating their enormously expensive assets where they have been locating them.
Houston floods. Often.
Houston gets hit by Hurricanes.
Houston is hot and humid with relatively high ground water tables.
Don't even get me started on the power and the durability issues arising from the use of sea water.
There's a lot to work out there. You put what you can afford to lose in Houston, but you don't bet the farm on coastal Texas. You just can't do that if you want resilient infrastructure.
https://news.ftcpublications.com/core/coastal-cities-test-se...
https://www.aoml.noaa.gov/phod/regsatprod/gom/sst_map.php