Because at least then then you don't have to deal with upselling, inefficiently speaking, etc. Some people like self-checkout. However, I don't see any advantage to a computer listening to my order and arguing with me (upselling) instead of clicking buttons in 1/10 the time.
Every drive-thru that has the monitor where you get to check your order for accuracy eventually starts displaying ads instead -- lowering accuracy and offering something you don't want.
One of the McDonald's near me has been using the order taking software in one of the drive thru lanes for a while now. It's such a better experience compared to probably 90% of the employees that have been taking orders there.
It doesn't have someone whisper/shout through the speaker because they don't know how loud they need to speak to be heard outside. It speaks clearly and can be understood which is not always the case with the bored and disinterested high school workers the store tends to hire. And my personal favorite is that I'm not greeted with "McDonalds! Thank you! Order please!" which seems to be the standard greeting they're training employees with at that location.
I've only had it get an order wrong once (though the food does still get made incorrectly about 10% of the time) at which point it quickly switched over to an actual person to complete the order. You can tell it's more efficient too because at busier times, the non-human order taker lane moves cars through at a two or even three to one ratio.
Overall, I'm surprised that more locations haven't switched to the software already and especially that other drive thru businesses haven't begun testing the software out here.
I’ve noticed they’re mostly staffed in the back cooking though, which is arguably a much better task for a human than recording basic information into a computer system. I trust a LLM to get my order right more often than someone who’s soul has been completely crushed by the banality of their task in life. At least making the food is actually doing something.