I agree that rates on BTC swaps are typically very low, and I have always found that weird, but it makes sense. Demand for shorting bitcoin is very low. I think it is mainly due to the fact that those who use bitcoin and have gone as far as to open an account to trade it are usually by that point "believers" in bitcoin. They are bullish, if they weren't, they would have just ignored bitcoin, and not started trading it. It is really weird though, because I am a "true believer" in bitcoin, and I think it will eventually be very valuable as more people see what an improvement it is on the current system, HOWEVER, thinking that its 5-10 year outlook is very bright has literally almost no bearing on where I see prices going within the next 30 days. So, since the max term of a swap is 30 days, it is very possible, and sometimes very probable that prices can go down over the short term, which is why I have always been surprised in the lack of interest in the shorting market. I think this is partly due to what I mentioned above, most people don't want to "root against bitcoin", but also, I think in general, shorting is less intuitive than going long, when in fact, a correctly timed short results in you ending up with MORE bitcoin, while going long ends up with you getting more dollars...

That being said, I think it also means that there is a strong case for short term shorting in that it is MUCH less costly to go short than it is to go long...if you figure the price will go up and down, you would make more by trading the downswings than by trading the upswings since the cost of your position, fees being equal, will be defined by the cost of the swaps (again, assuming that prices swing up and down, or in other words, holding the viability of your trading strategy to be equal).