Since NVIDIA started comparing apples to oranges, like in Ada vs Blackwell and Blackwell looked twice as fast, but they were comparing FP8 vs FP4, and it was only visible in small print: I believe it when I see it or when independent reviewers confirm it, but even if it's a 10% VRAM reduction in real games's content, that would be something (of course, if everything remains the same, that is).
So this texture compression happens in real time and requires, I assume, some kind of special cores to do the compression, which would require additional energy. (again, as said, if everything remains the same and it doesn't lead to less energy efficiency e.g.).
But it can be a win as DLSS upscaling generally has shown.