If Ethereum is a utility platform and the value of its coin rises, how can it continue to be used as a utility when its used as a store of value?
Most people that buy Ethereum aren't using it, they're trading.
If it is trading then it is not in store. It is being used just for a different method.
Another usage is the means to buy other coins. Bitcoin and Ethereum are the most used for buying ICO tokens and also user to user trades. It is still way faster than any tokens that came out there which is just copying everything from bitcoin and ethereum.
It is still way better to use the pioneer and trusted than risk it for a scam coin.