The savings might not directly be passed back to customers in the form of lower prices, but we might see the cost savings being used to prevent or limit price increases.
Inflation is always a factor and this year especially so. However, McDonalds had a 99p menu here in the UK (I presume other countries have similar) and this year some of the prices increased to £1.19, which was the first increase of these menu items in 14 years.
Maybe the cost savings will help prices stay static for another 14 years? This is quite important if McDonalds will remain competitive in a price-sensitive market for non-necessity items.
As a sidenote on customer satisfaction - I love the current automation in place. As a teenager I would queue for ages, at busy times, to order my Big Mac and had to explain to a person that I didn't want any sauce, relish etc. I hated that. Now there are many more kiosks per customer and I can even place my order on the mobile app and head straight to the pickup area. I can do all manner of customisations without having to speak to a human.
Several of the casual dining restaurants I frequent have adopted similar ordering automation since the pandemic. Typically they give you a QR code to order from an online menu but they also have the option of going to the counter if you really want to order from a person.
The concept probably works well in fast food and casual dining, but at more premium sectors of the market customers will still of course demand and expect a waiter/waitress and more human interaction.