Having an energy storage system at the bottom of the ocean is a new and innovative idea at the same time, which can have a good development in the immediate future. And the reason is very simple, every day are installed more wind power generation systems on offshore platforms.
The energy produced has the "problem" that it is either consumed at the moment or stored, and storing it for use at another time when it is needed is not easy, and there are all kinds of proposals.
What the company Ocean Grazer is doing is developing a battery at the bottom of the sea, which they have called Ocean Battery and which stores energy just below the generating wind tower.

It is a very simple system that does not require special or complicated materials, and the technology has been available for many years. It involves transferring water from one tank to another. When energy is left over, part of this energy is used to transfer water to a higher container and with that we store a potential energy.
At a given moment, the water can be made to pass back to the lower tank and in doing so it moves a turbine that generates energy.
A video can be seen at: https://youtu.be/GbTsgWD_ZMU
It is a fairly simple system, non-polluting, etc… and I see nothing but advantages, and perhaps the only possible drawback is that the company does not indicate the energy storage capacity. Although it is clear that it will vary with the size of the deposits.
This energy storage can be applied to new and old offshore wind generation platform installations, and there are many thousands of wind turbines all around the world. With which their business possibilities are quite large.
I wish the best to this new company, because we all need it.