What is the practical difficulty in bringing a NFC card like Chalo for transportation across Kochi?

I still see pvt buses having this paper stacked ticked instead of tvm. Is it difficult or they just being selfish so that they can charge more from unknown persons? Bringing such cards can unite transportation throughout the city. I know there exists Kochi one card but it is non practical, charging for every recharge, also not used everywhere. Thoughts?