You can make the gil legitly. There are alot of ways of making money. The problem is this isn't what was promised and many people didn't anticipate buying a sevond FC house just for themselves. I doubt anyone would use bought gil on a personal house. If they did they'd be pretty stupid. Buying gil in itself is pretty stupid.

SE made spiritbonding a bit more beneficial, if you're lucky. More gil should be floating through the economy. Hopefully legit gil, that is.