I don't know where this guy comes from. But, USD15/hour is a very high rate in many countries. Or, he is just trying to build up his portfolio and get his name out there.
This seems like a very good approach to attract people attention.
But it's completely different if the person works in the IT industry. I do live in Brazil (Sao Paulo), and I can't hire a GOOD web designer for my company paying less than $3.000 USD/month (R$ 5K). Here, an experienced designer can easily ask $5K USD/month for working fulltime.
Out of curiousity, are people with these jobs considered high status in Brazil? Is the profession held in high esteem in the sense that being a Doctor in the US is? That seems like a lot of money compared to the median salary, and I'm trying to imagine what impact salary discrepancies like that would cause.
Consider that the middle class is only 15%~20% of the population in Brazil. So if you have a university degree you're automatically high status.
Also, IT jobs pay in average better than most white-collar jobs. An IT manager or a very good lead developer might even make more money than a mediocre doctor (but that's true in US too, I guess?). That said, given that there's no regulatory barrier to entry, IT professionals in general aren't seen as high status as doctors or lawyers.
This seems like a very good approach to attract people attention.