A delivery person working for the restaurant works for the restaurant, and has reasons to care about both the restaurant and the customer - and in return, both have a reason to care about the delivery person. DoorDash, Uber Eats and friends are VC-funded multinationals that ruthlessly exploit restaurants and the delivery people, strip-mining the local markets, often ruining restaurants in the process. The mischief and borderline fraudulent behavior of those companies is well-documented, and regularly discussed on HN.

> How is that any different than if the delivery person worked for the restaurant?

As far as I know, at least in Europe if the person works for the restaurant they have almost always a right to days off and always for sick leave and contributions for the pension, while the delivery companies try to make them figure as "self employed". Laws are being passed (most recently in Spain) to avoid this issue, so this might not be the case everywhere anymore.