And I think you're falling into the same trap of believing other economic actors will happily agree to your proposed "solutions".
Disadvantages of NFC payments:
1) economic friction which lowers supply of drivers: drivers have to buy $50 NFC terminal from Square. $50 is not a lot of but it's extra financial friction which deters potential drivers
2) trust issues which lowers supply of paying customers: NFC payments puts the payment amount in control of the driver which makes potential customers fear getting scammed. In the Uber/Lyft model, this doesn't happen which is a significant psychological advantage because drivers are notorious for playing games with payment (especially with foreigners and travelers). By letting the "service in the cloud" pay the drivers on behalf of the passengers, it adds accountability.
I'm not claiming it's impossible to create a car-on-demand service that uses NFC and/or credit-card swipes. I'm saying it would be a disadvantage to other platforms that work more conveniently. This means less paying customers which leads to less capital to continuously improve the software -- which could then lead to more customers abandoning the co-op rideshare app for the more polished Uber/Lyft apps.
Again, see the failed non-profit RideAustin losing riders as somewhat analogous case study. And see the other comment about the apparent low quality of this thread's app (Drivers.coop): https://news.ycombinator.com/item?id=26592354
The co-op needs capital to improve the app software and you need a virtuous cycle of paying customers that don't avoid (or abandon) the platform to provide that ongoing capital.
>co-op would not have to make riders create accounts and associate payment information with them. That removes some complexity for the user,
This wouldn't be an advantage for commuters that use Uber/Lyft daily.
The obvious answer would be "so that the user doesn't have to have the app", but if the user doesn't have an app, how is that different from an old fashioned taxi service?
Beyond the fact that the credit card terminal isn't broken... but it's not like the rider would know that ahead of time.
Heck, a large fraction of the passengers won't even have to reach into their pocket to get their phone because they'll have been doing stuff on it during the ride.
Even for those who have to use an actual physical credit card I don't think it would be enough of a barrier to make a noticeable difference because they are also using that card for nearly everything else. It's so routine that they don't think about it or notice it. I don't think I've ever heard anyone complain about the complexity of paying by credit card at a non-waited restaurant, a grocery store, a hardware store, or any other retail place.
Also, note that with this approach the co-op would not have to make riders create accounts and associate payment information with them. That removes some complexity for the user, and is one less thing to deal with when the user gets a new credit card.