I'm not sure how it's working. Maybe Uber is currently eating a part of the costs to gain market share. They handed out very generous 4x 15€ coupons last year for new users. That was when I signed up for Uber Eats.
I started before they cranked up the exploitation and quit as the terms got increasingly bad.
I don't even think they ran a profit at that point, so I guess everyone was getting screwed