to clarify this argument I guess I would have to see some definition on what exactly this means:
You could achieve some scary computing densities
as rjk said, computing density is the amount of instructions processed in an amount of space. a high computing density is powerful computing power in a small space. water cooling allows you to almost disregard airflow, so you can put chips/boards closer together, squeezing more in a smaller space. additionally water cooling hardware generally takes up less space in the box than air cooling hardware.