I mean gigawatts is a concise metric to get a grasp of the amount of gpu compute they install, but the honesty seems a bit strange to me imo.

Total gigawatts is the maximum amount of power that can be supplied from the power generating station and consumed at the DC through the infrastructure and hardware as it was built.

Whether they use all those gigawatts and what they use them for would be considered optional and variable from time to time.