The price of the bitcoin is unstable, a month can go up to 50% but could drop by up to 50%, it is very risky for the corruptor to save money because there is no money opportunities bitcoin runs out.
Funny you consider this as an issue for the corruptor, although this not seems to be a big problem for them. As long as they store and keep their bitcoin no matter how low the price of bitcoin at the moment, they can still wait for it to increase. I think the biggest reason of them using bitcoin is that to hide their corrupted money so that they will not easily get caught.
We must remember that the bitcoin fluctuations are still balanced even though they are often up and down, we can see the current bitcoin prices, and if viewed from corruption, this is not a big deal because the most important thing for them is by Washing their money as much as possible, depreciation is inevitable , Bitcoin is not money that can be lost and this is the entrance to speculate from corruptors.
That's right! it is not a problem even if the price of bitcoin will suddenly get low for some reason, all we know is that it will also go high after time and the corruptor just have to choose a perfect time to withdraw his/her corrupted money. The point here is not the price of bitcoin at a specific time, but the ways that bitcoin can be used and lead to corruption.