Earlier quoted context omitted.
The point is generally to recover cents on the dollar from money you can't otherwise use. Imagine you have a network of people moving illegal drugs. They collect money from their customers, and they need to pay it to you, the supplier. Arrange for them to eat a lot of food at your restaurant. Maybe they shout their friends. The money goes into the restaurant, and is mingled with other money. That money is used to pay…
Requiring your henchmen to eat a lot of Kebab all the time is not at all a scalable money laundering scheme. It's also self-defeating since they will become fat and sickly from too much Kebab :-(
Buying the liquor gets a bit fuzzy as to where the money comes from. But the bigger thing is you can have imaginary customers and either drink “their” alcohol, pour it down the drain, or use it for gifts and bribes, all while booking receipts for people who never came into the bar at all.
It’s not that the henchmen spend every ill gotten dollar in the restaurant, it’s that the restaurant looks busy enough for that level of revenue to look even remotely plausible.