ETH is what you use to pay fees to the network to transact on it. i.e. if I want to transfer you some "tokens" on the Ethereum platform, I would have to pay a f

ETH is what you use to pay fees to the network to transact on it. i.e. if I want to transfer you some "tokens" on the Ethereum platform, I would have to pay a fee in ETH. This makes it a speculative investment, since if more people want to use the network, there is more demand for ETH as a currency. Since there is not an unlimited supply of it, there is a supply-demand dynamic on ETH as a currency.