everything on market that exist has been touched by hands of corruption on some level, user being anonymous can use this money to buy drugs ,illegal ammo or what not .but every currency is prone to same ,even gold can be used for corruption. corruption is anywhere where there is money ,people want all the money in world and some of them can cross limits to get so. bitcoin emerged from darkweb and now its getting mainstream but as you mentioned there  are politicians who can benefit from it even when its fully implemented as the currency of nation .