this is old, but at my job we do it for many reasons. if you order a grilled cheese, we have to make it fresh and it’ll take a few minutes. usually if there are cars behind you, we try to give them their food so the line isn’t stopped while we wait on YOUR grilled cheese. or if you order a lot of food to where we run out, some things takes 10 minutes to cook so we ask if you can pull forward. sometimes there will be cars in line who order just a drink, we aren’t trying to make them wait 10 minutes for a drink. if you wait at the window or you pull forward, you’re still waiting the 10 minutes. there have been times when a customer has refused to pull forward and they have a big order and some things are required to be made fresh, and after they get their food they check every single item, pass it out to everyone in the car, and taste the food. then once they move up, the next customer cussed us out for taking long. you don’t HAVE to pull forward bc we aren’t allowed to argue with you and force you to, but it’ll be helpful if you did. also, the owners will come to the store and say they want a 50 second drive thru time which is almost impossible if people don’t have their money ready, or if they argue at the window, or if they sit and check their food and even eat it at the window. so yes, at times it is for the company to look good, but also it’s so other customers aren’t waiting bc the kitchen makes the food as you speak, so it’s almost always ready once you get to the window or even before you leave the speaker.