When I worked in a laundry mat back in 1980, it was only about $1 to wash and 25 cents got you about 15 minutes with a large dryer. So it was practical to use a roll of 40 quarters, or buy a few from the dollar changer to do a whole week's worth of laundry at once.
Nowdays, with the cost being over $20 to get a few large loads of laundry done, and spend 30 minutes on the larger commercial dryers, it is much more practical to have coinless laundry systems. They can offer the following advantages.
Lower costs on special days (so on a slow Wednesday or Thursday, they can offer special pricing, like reducing the cost by $0.50 per load, or give a extra minute of dryer time per $0.25 cost).
Offer a card recharge value of $22.00 when you use a $20 bill to refill the card (so 10% free) was offered at the laundry mat I used to use.
Make it much easier to keep track of your income (if you own the laundry)
Keep the shopkeeper(s) down the street from bringing over $10 and empty your quarter changer for their own use. Running out of quarters can be a problem in some laundry mats, I have seen signs that say "Customer use only".
Prevents the need to have each machine emptied each day.
I was reading a "Laundry" owners magazine when I collected most of this information about a laundry mat. I do not own one.
Fred.