People like them though. Look at the Starbucks on Douglas across from Mayfair. Why deny people what they like?
It's not a net benefit for society, given the totally needless emissions released, the atrocious quality of food provided at such a convenience that it only exacerbates the negative health impact. Wasted land needed for the vehicle infrastructure, increased conflicts with other modes of transportation at both entry and exit points. They also encourage people to eat and/or consume hot liquids while driving, which is pretty stupid given the duty of care you have when driving a vehicle, especially in an urban environment where pedestrians often outnumber vehicles. They also de-prioritize the actual in-restaurant service. It's well known you will be served faster at drive thru for Starbucks than at the counter because they will escalate drive thru beverages. So that's just another incentive to drive vs. walking to the location.
And quite simply they're a symbol of what's wrong with our society, where we value convenience over quality, and don't give a damn about the repercussions.