If you're worried about the environment, recyclable paper stubs and small plastic/magnetic strips all seem pretty preferable to building, maintaining, and replacing hundreds or even thousands of high-precision sensors across a city.
The power draw from a camera is probably always going to be higher than the power draw from a short-range NFC reader. And the NFC reader is also probably always going to be less delicate and last longer, which is good because the environmental downsides of throwing away paper are negligible compared to the downsides of sticking electronic components in a landfill.
The power draw from a camera is probably always going to be higher than the power draw from a short-range NFC reader. And the NFC reader is also probably always going to be less delicate and last longer, which is good because the environmental downsides of throwing away paper are negligible compared to the downsides of sticking electronic components in a landfill.