Hitting osf=money Selling pots=money See the connection? If they didn't bank their money in pots it would all get taken by people when they're not in a pwar.
If osfs didn't buy pots then their money would get taken quicker because the more you have out the more people take. So they buy pots and they have less money out so the less money people take and thus the osf can stay open longer while still supplying a substantial amount of money
You drop pots so that you dont have money out all of the time so that you are open when you are online. Instead of leaving money lieing around to be taken.
Banking=putting money into buying pots so that you can then later om sell the pots for $ Pots=potions Osf=open steal/spy farm Oaf=open attack farm.