We've definitely seen some outlandish attempts at improving or outright replacing the humble credit card, but South Koreans will soon be able pay for purchases using the most easy-to-lose system we've seen yet -- by inserting a special USB flash drive into a slot. The system, which is being rolled out by Shinhan Card and VIsa, also lets users pay for online purchases by sticking the drive into their computers' USB ports, and Shinhan is also rolling out new terminals that will enable contactless payments using the device as well. Of course, the drive itself is locked down tighter than a drum, but we still aren't convinced a bulky flash drive is a better option than phone-based or biometric payment systems.