In reality it was actual cash money. He couldn't use banks due to his money being gained through illegal means. He had stacks of money just laying around so much he couldn't really secure it. Columbia is generally warm and humid so a lot of pests like rats and insects. I heard he was spending around 10k a week just on rubber bands to wrap the money into stacks of a thousands.

If you don't know he made most of his money by selling cocaine though.