that's when the app shines. You basically cut the ordering queue, which drive through users cannot avoid at all.

Also even if stuffs are prepared in chronological order, they don't literally need to fulfill everything in earlier orders before starting to work on the next one. In drive through if someone order something that takes longer to prepare it would clog up the queue that someone might not be able to even start ordering. The lack of parallelism is very visible especially when you do a walk in order and order very few items right after someone who orders a lot, you will often get your order first, despite their orders' preparation started before yours.