Uber is at a large enough scale that this analysis doesn't work. You and I do not care even a tiny bit about "Eats for the Way", one of their planned features this year (https://www.uber.com/us/en/newsroom/go-get-2026/) that lets Uber Black passengers specify that their car should arrive with their Starbucks coffee order. But if 0.01% of users order 1 additional ride a month because of this, that's about 200k rides a year, which may well be sufficient to justify the development costs.