Teaching mathematics is a huge and important part of the mathematical endeavour, but that's not all that there is to it, and I don't think that's what Bourbaki was trying to do [0]. No one should
learn, at least not initially, from a Bourbaki book—a sentiment with which I expect even his, uhm, constituents would agree [0]—but I suspect most professional mathematicians find the Bourbaki œuvre useful as a reference, both for facts they know that aren't otherwise written down, and for facts that are on the borders of their expertise and require only a spot check to confirm or dispute. Certainly I use it that way.
[0] EDIT: I am wrong about this historical fact, although I believe it doesn't change my point about modern usage. Wikipedia says:
> While teaching at the University of Strasbourg, Henri Cartan complained to his colleague André Weil of the inadequacy of available course material, which prompted Weil to propose a meeting with others in Paris to collectively write a modern analysis textbook.
(https://en.wikipedia.org/wiki/Nicolas_Bourbaki).