Definitely. Don't get me wrong. I constantly work my ass off to make gil, it's just that there is no reason for me to save it when there is so much cool stuff to spend it on. After all, what good does it do you to not spend your gil? It's not accruing interest. The cost of items however, does rise and fall like the stock market. In the rare times that I do find myself with multiple millions, I spend it on items that are priced too low in my eyes and resell them at a profit. Your gil can't make more gil while it's just sitting in your inventory.