Suspect two reasons for this change.
First and foremost the cost of and operating expense of the machines.
Willing to bet that payout in bills only machines are less expensive to purchase and maintain.
Also the loading does not require sacks of coins.
Lastly there is a VERY small plus for the house in 'keeping' the change. But over time it does add up.
Suspect the days of the TITO are somewhat limited and soon everything will be on your card.
Wishing all enough,
Dick Staeffler