South Korea to Experiment with System that Will Allow Foreigners to Use Credit Cards to Pay for Public Transit
This is actually a pretty good idea to make using public transit easier for foreigners. With that said it is not that hard to figure out how to pay for public transit in Korea:

The government has begun reviewing a system that would allow foreign tourists to use buses and subways in Korea with overseas-issued credit cards, officials said Sunday.
The land and transport recently launched a bid to commission a study on introducing an open-loop public transportation payment system, which was to begin this month and run through the end of next year, according to the officials.
The study aims to enable foreigners to pay public transportation fares directly with international credit cards. Currently, visitors must purchase and top up transportation cards with cash or buy prepaid cards designed specifically for foreigners, which often causes inconvenience.
You can read more at the link.

