The Church of Jesus Christ of Latter-day Saints states, "for longer-term needs, and where permitted, gradually build a supply of food that will last a long time and that you can use to stay alive, such as wheat, white rice, and beans." So, the main purpose of this longer-term storage is to help us "stay alive."
A lot of people get hung up on the fact that they don't really use wheat or oats or whatever. If you don't already use these whole grains that store well, I recommend that you acquire the grains and then work on cooking with and incorporating these foods into your diet. And remember that "grains" doesn't necessarily mean wheat.
Because whole grains are hard on digestive systems, it is also important to help your family tummies get used to those grains. I definitely DON'T recommend buying grains, storing them for 30 years and never using them. If you need to, set a goal and learn how to use these grains. Whole grains are not only good for your longer-term storage, but they are also good for your body.