I like that approach. While the student thinks that they are getting something of a "freebie" (or a half-freebie), what they are actually doing is learning the subject material. Which satisfies the purpose of the class.
Speaking of learning to study (this was some 15+ years ago), my Econ 101 instructor allowed us to create a 'cheat sheet' for one of our tests, but the rule was that we could only use one sheet of paper. I got several chapters of information on one sheet. She commented that I had rewritten the whole textbook.
I took her for Econ 102 also - she only allowed an index card for that test. :-)
Anyway, it turns out that I barely needed to look at the cheat sheet. By creating it, I solidly planted the logic and information into my own mind. In the process of making the sheet, I was learning the material.
That’s quite a “cheat sheet!.” I’m not the least bit surprised that you learned a lot by putting it together. Smart teacher, smart student!