This is a fascinating idea IMHO. A couple years back I was toying with the idea of whether multiple gyroscopes could be combined to make extraction easier aboard a vessel. The limit I see is how difficult / practical the mechanism to convert procession to usable energy would be. I'll have to dig into the paper itself.

The tunable frequency adjustments would make wave energy much more useful for a range of applications!

Interesting. This company also harvests wave energy, but a much lower scale (and primarily uses solar) https://en.wikipedia.org/wiki/Ocean_Power_Technologies

I would know because I lost money on the stock :)