Judging from this rando laundromat youtuber I saw a few months back, that's basically a closed circular coin economy: you put bills in the money changer, then coins in the washers and dryers. The owner then takes the coins out of the machines and puts them back in the money changer. In that scenario, bills are what enter and leave the laundromat.

But in a regional coin shortage, someone with spare time might just choose to loot the coin machine, and gum up the internal coin economy. Banks are apparently offering an extra 5 percent on coins: https://www.kctv5.com/a-bank-is-paying-people-to-bring-in-th...

This does remind me of the stories a few years back about credit card churners buying coins from the us mint in bulk for the cash back, then depositing at the bank before the bills came due.