... the price fall is more than the rise
WRONG.
you need to look at the bigger picture.
right now you are just looking at a short period of time where bitcoin price has came down a little. if you look at a couple of months you can see a rise from ~$880 to $2900 and right now it is sitting between $2200-$2400.
even if it falls more it will still be much much higher than the couple of months ago.
with that said, did you get your answer to why people hold bitcoin
I suppose that OP is referring to how fast the price is going down, not by how much.
For the OP: I would say that the dynamics regarding "how fast" is similar to the stock market. Actually you could model that using an inverse correlation between volatility and delta price returns.
There are a few papers trying to say why. It seems that their conclusion is related to the fact that when the price starts to fall, panic is creeping into the market.
So there you go, market behaviour at its finest.