According to: https://math.stackexchange.com/help/dont-ask
You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page.
It seems very strange to me that questions asked at MSE should always be practical. The questions that fits this guideline most (practical,answerable and actual) are homework problems. This guideline seems to apply more to SO. Isn't this help center giving users the wrong impression of what sort of questions we want at MSE ?
For example, one could interpret "based on actual problems you face" as that questions out of curiosity are not appreciated at MSE.