I stumbled on this by accident, I had wondered why my Uber rating had dropped to 4.5 for no good reason. Uber needs to stop advertising as cashless, I assume the tip was built in to their fees, but clearly it is not. No other reason for my rating to be so low.
I love the cashless concept, we do have another company in Montreal called Teo that is truly cashless, I will use them more often as they pay their drivers an actual salary.
I totally am happy to tip drivers, but I want to be able to do it on the app. Works well for my kids too.