I have read your Quora post and I agree that the credit card system is antiquated, outdated and leaves a lot to be desired. I certainly feel this as credit card user and as a member of the startup community who knows the possibilities that are out there. I wrote the article considering the perspective that when Square started I was rather skeptical, it felt like a bit of a gimmick, yet their latest update suggests they are moving away from merely providing a piece of hardware that allows a merchant to accept credit cards and considering a more holistic system.
The new direction is at least interesting as the introduction of Card Case means they could the a customer's identity and credit card to their mobile phone and I can't see why down the road they couldn't use a variety of fund sources, i.e. not just credit cards.
I do think Square has a long, long way to go.
Where they started has given them some traction to date and I think that's because at this point in time, albeit antiquated, credit cards are well understood. In my opinion it's good to see Square adding extra features to their initial offering as I think it will need to in order to survive.