Personal stores have more legit uses than you're giving them credit for. Setting up a shop with crafting materials right in the crafting hall will generally net you more money than selling stuff on the broker, where people have to teleport back and forth to go between (in sanctum anyway, I think Pandaemonium's were closer). Same thing with sellable quest items. Also, with a limit of 8 or 10 items on the broker, and 8 characters across your entire account, it's very easy to run out of selling space if you're a power seller like myself.

Granted, I generally have one 999m item in my store as well. I don't mean any offense to any particular player by doing this, I'm just calling out NC's poor server management.