DigitalRev interview questions

I was contacted via email a few days after applying online and came in for an interview immediately. The interview was scheduled for 2:05PM, I arrived at 1:55PM and waited until 2:50PM to be interviewed. They were not willing to sponsor a work visa and I was shocked to find out that the salary range was 10k-13k. The position was advertised specifically for native English speakers. Why would a native English speaker work for half of what they can make as a teacher in Hong Kong? Interesting company but not what I was looking for to say the least.