If you have access to a secure structure that is already built and safe to inhabit … Great. That is not always going to be the case.
I have had to use what I learned in shelter building twice so far. Once when I got caught in a blizzard and once while mushroom hunting with my children. You just never know when this knowledge could save the lives of you and/or your family. Knowing how to build a survival shelter is a vital skill for if SHTF!