Does this price inflation and deflation depend fully on
Bitcoin days destroyed? I guess it also plays an important role because one may send his own coins between different addresses trying to show the network that several transactions are being made?
Yes that measurement is somewhat accurate (although I`m not sure how accurate) of the money velocity.
The slower the money velocity the higher the price.
So when prices go down, its a bad thing because consumers will hold off on spending because it might be cheaper tomorrow?
I`m not sure we can talk about a consumer base in bitcoin yet, we are too few to make any study on this.
If bitcoin price goes down, thats bad for anybody who holds bitcoin obviously, and prices go down. Only good for loan takers, because they get chep loans.
If price goes up, then its good for holders, and consumers, because they get the same stuff cheaper. However loan takers get fucked as their loan size is increased too.