Since you are immersed in salt water, any sort of agriculture will either involve serious halophiles or highly efficient closed loop freshwater stuff. Hey, look, if you have the tech to manage that in a more or less cost-effective way, you can have your pick of the earth's presently unfarmable deserts, without the cost of pressure resistant naval architecture or the risks of running out of air. Plenty of wind and solar power, too.
The desert would require buildings/houses that can reflect quite a bit of sun rays. If it doesn't, houses will start to cook people. Having that much heat, sand, and wind will make having open houses impractical as well.
Having water to make farmable land isn't enough. The plants need to be able to survive the extreme temperatures in the desert.
All in all, undersea housing and desert housing will probably balance out, due to the fact that it is much cheaper to create heat than to remove heat. At the very least, you'll get a large supply fish in the ocean.
If you can generate substantial amounts of electricity, by some workable means, for your little underwater habitat, this implies that you are just an extension cord away from being able to bring large quantities of electricity to whatever coastal region you fancy. Loads of unused or underused coast that would be quite pleasant if you had the energy for some desalination.
Well undersea power generation might not involve a coast at all. The issue is how long of an extension cord will be needed to bring large quantities of electricity to any coastal region.
Living in the ocean may not be practical, but it is an alternative to other areas in the world.