Lowering monthly commitments (in my case, by $2,900/month since paying off my mortgage in full 17 years early on a 20-year loan) means that if I lose my job, I will be able to get by on much less money. It also means I can invest more aggressively each month, since I add that $2,900 to my stock portfolio every month. I feel more economically secure and sleep better at night.