It doesn't have to be in the middle of the ocean to be less accessible than an on-ground data-center.
Even if it's in a giant pool next to an any existing data-center— accessing a machine that's underwater probably takes longer and is more likely to affect the operation of other machines than if it were on dry land.
Even if it's in a giant pool next to an any existing data-center— accessing a machine that's underwater probably takes longer and is more likely to affect the operation of other machines than if it were on dry land.