[maipen]

Not only that, the Proof-of-work system also is prejudicial to holders. Miners are constantly dumping their newly mined coins to pay for there astronomical electricity bills. (constant selling pressure isn't good for the price)

Also, most of the mining power is always in china, so that isn't good. Mining is very centralized, miners can just join forces and 51% attack the network, which seems unlikely but not out of this world. It surely can happen, specialy if they find a way to be very profitable. 51% attack a network, or using exploits isn't illegal.