Can we stop doing this? Our free time has zero monetary value. Every minute of our lives is not billable, and it's disingenuous to frame it that way.
Sure, avoiding 40 minutes of driving time might be worth $10 to you (it is to me, too), but... just say that, maybe?
And I agree with you in general that the grandparent's example was maybe not the common case. Sure, sometimes people get late-night munchies and make a small delivery order to Taco Bell, but I would hope that most orders are at least for a single, full, lunch- or dinner-sized meal, and will often be for multiple people. Delivery is still certainly more expensive than going into the store, but not having to deal with driving somewhere to pick it up also has value to many.