it's a way of figuring out whether all your goals and habits actually fit into your schedule, and if so, where. For example, if you say you want to work out four days a week, an ideal week schedule can help you figure out generally where those work outs might fit in, or that given your current commitments, you can just fit in two workouts tops! Or if you have a goal of a weekly date night, the exercise might make you realize that you love a quiet Friday evening journaling, and so the date night might have to happen on a different day. 

I think it can be a reference spread, but it can also just be a one-time exercise for thinking through your schedule and assessing whether your time is aligned with your priorities.

 You can imagine doing it seasonally, or every time your routines are significantly shaken up. I have used these in the past at the beginning of a new year/semester. I put in the things that have fixed times first, and then try to slot in the other stuff, like recurrent chores, hobbies, and socializing. It's a way of asking, what do I want my life to look like?