For me, the point of FI is two-fold. First, I want the freedom to think. I find that I spend my day very differently when I have an obligation in it, however small. So, if I have a lunch scheduled at 1:00, even if it is something I am looking forward to, it changes the tone of my day. I'm now "on a schedule", and I (consciously or not) try to optimize my time. Verses an obligation-less day, where I spend my time unstructured. I still do things, but they tend to be the "important-but-not-urgent" type tasks, and I do them at whatever pace suits me. I get more "things" done on the optimized days, but I am far more creative on obligation-less days. I know I will still have plenty of obligations in FI, but I hope to increase the number of obligation-less days I have.
Second, my experience with foster kids has made me realize that we cannot be a two-income household with children. Life is just too busy and too crazy and I would go totally mad. However, neither DH nor I feel we would make good SAHPs. So, we've opted to delay childbearing until we can either both FI or semi-FI and work part time from home.