Some of the candy shops in Denmark seems to be used for money laundering.

Most candy is cheap to buy in volume and you just discard it rather than handing it to customers. Everything looks fine in the books. You just don't have as many customers in the shop as the accounting books says you have. You will have to pay tax on the laundered money but that can be a small price for making the money fully legal and usable for e.g. house loans.