Taxi drivers in Hk don't want payment systems that leave a tax department scrutinisable paper trail.
Cash is king in Hong Kong Taxi Land, and until someone develops a payment system that that IRD can't get access to the account, you got no game. Now that there are much more pervasive anti laundering policies employed by banks and the like, then the chances are, the taxi industry is just going to say F off to 20th century, first world, convenience. You cant even get cab charge books here ! ( taxi voucher )
Most of HK runs that way, which is why the hk IRD collects so little income tax, compared to say, Australia, which collects a shit tonne more per working person... Kinda helps when house hold incomes in Australia are considerably higher than Hong Kong on average. Not that Hong Kong really gives two fucks about the ' average ' Hong Konger....
And for the above stated reason, Hong Kongers don't really like taking financial responsibility for anything, even with such low % income tax, the mass majority don't declare enough to even pay tax... Hmmmmm
In my opinion, the whole taxi industry chestnut, needs to be busted right open, and the present 3 colour taxi system, abolished!
Make taxis forced to be managed by a brand, and brand that taxi company and its cars accordingly. This creates competition between cab brands, it will also fast track android phone, GPS linked taxi hailing services ( which work amazingly well on the mainland ) Octopus card etc etc etc.
The problem in Hong Kong, is the present lazy arsed structure of the taxi system, eliminate that, and allow taxi companies to run competing, branded ( uniform livery) fleets, then customers will choose one brand over another...Competition ! something Hong Kong usually does its level best to avoid. hahahaha