not necessarily, but it can be a good idea to have a distributed, tamper proof ledger of transactions.
that way anyone can provide proof for basically anything to do with the service: payment, drive, location, etc.
it might also have advantages from a security perspective for riders and drivers.
there are advantages, they’re not entirely necessary, but they may well be the best option for a distributed network (i.e.: no central server infrastructure, at least not beyond some simple software repository for downloads/updates)
because the class system is built into capitalism.
you can’t have unchecked capitalism without an exploited underclass.
and you said it has nothing to do with the economic system, which is false, hence the downvotes…