I'd say traders are expecting large price movements. We have gone down a lot and crypto is far more volatile than stocks or bonds. When prices move, they move a lot. For most traders $3000-$4000 range was the lowest or second lowest bottom they were expecting. After a loss of lots of volume, markets can take a sudden shift with a massive spike.

I've done some margin trading on X5 leverage and the current situation would have made me extremely cautious. Bitmex offer far more leverage and imagine what even a short bull trap could do on high leverage. That's my theory on low volume. The is not in a clear bull or bear phase anymore. Making bets is risky.

Those who made money now have a lot to spare and even the ones who stayed out could very well be expecting large price movements and they could be making bets away from the 10% range of the price. This is just my personal speculation.