Ethereum is really not a currency, per se. Rather, it is fuel that is going to be used as "gas" to fuel the robots on the Ether network. Ethereum will be consumed in this process and a corresponding amount of Ethereum generated through the POS method once the POW mining is complete later this year or early next year. All the entities running bots on the Ether network will need this Ethereum to fuel their applications. This is the method through which Ethereum derives its value.
The question that I have for someone more knowledgeable than me is this; is Ether classic also "gas" for the Ether Classic network in the same manner as Ethereum is for the Ether network? If you understand this relationship, please let me know.