I check on Bitoffer's web, there are 2 mode in BTC Seer option. In classic ‘option’ mode, you can buy put or call for 1 BTC with just 1~9 USD, and you can earn how much BTC price changes in the time limit. For example when BTC price is 8000USD, buying 1 BTC need 8000USD, make call option just need 4USD, when BTC price raise to 8100USD, for  BTC spot just make 1.25% profit, in BTC Seer Option you can make 2500% profit.

Higher interest and lower risk. LOL