[isaacb]

It's not really an issue for me. I have four cards and don't mind having them all in my wallet. What seems to have happened is a bunch of people with the same idea panicked and put out releases at the same time to avoid looking like copycats.

[dangrossman]

They weren't all put up today, just re-submitted to HN by various people today. Both the Wallaby and Protean Echo sites are from 2012.

[skygazer]

Oddly, for me, the killer feature on the "Coin" card is the proximity alarm if you leave your card behind. I've repeatedly left my card at restaurants after paying, or left the house in the morning without my wallet. Err. However, I would hate to have to bring my credit card with me when I go for a jog.