I'm not sure I understood the solution there. Storing only 0.1%-0.01% of the interesting metrics data makes sense in the same way that you'd take a poll of a small fraction of the population to make guesses about the whole?
I believe he means they are storing all the data, but for a subset of types of data, sorta like extracting just a few columns out of a big table. Presumably someone on some other team gets use out of having access to the 99.9% of data stored that is not relevant to "performance or capacity related queries."
