In some ways, it feels like cosmic balance that DT gets priority. Hear me out:

In the DT you are placing yourself at the mercy of every order before you. A delay to the front order at the DT in a peak time delays every car that's entered the queue. Maybe as many as 8 orders. So a delay of one minute there wastes 8 human minutes of life.

At the counter, on the other hand, it's not serial of course, so a delay to your individual order affects only you. So, even by old-fashioned good business sense (rather than modern MBA KPI-optimizing logic), it's reasonable to waste 2 minutes of your time, instead of one minute each of a whole queue at the DT.

(Yes, you can park the delayed car at the DT, but trust me, that's not a sustainable solution to do routinely. In general, getting "behind" during a lunch rush is an extremely tough and frustrating ordeal for the whole crew, no matter what)