I see why you ask, I need to explain better in config.yml

You have to options. Check "drop-money-use-item-as-currency"

1. if true then you must let your players have access to /mh money sell ( or /mh bag sell) while holding the bag of gold. The advantage using this method is that the player can save his money in a chest or on the ground in a protected area.
2. if false the bag of gold is converted to money when he picks up the bag of gold.

I will add a better explanation in config.yml in next release