Almost sounds like a bunch of people crowdsourced a better textbook than was otherwise available to them. If your database is truly "secret" how are people going to add to it or benefit from it?
Sure if the field of study is about memorization, you did learn.
I'm not sure that exists though. There are challenges where that is indeed the entire "field", e.g. Pi digits competition, but otherwise for most if not all fields, it is about having enough knowledge to answer questions that have no yet encountered. They might be variations of questions you know but they are not verbatim the same.
Ideally learning about a field should even lead you to be able to consider, warranting you would have the resources to do so (e.g. time, experimental setup, etc), actual unanswered questions from the field.
So no, IMHO in most cases memorization is not learning.
I never understood the concept of "learning questions from previous years is cheating". Like, does the entire field of study answer hundred questions and that's it? Or is the professor just too lazy to invent new questions each year?