I think Bitcoin's one use case as a banking system to take over a $20 trillion+ banking system is far more than enough. The average person isn't going to care about "my money can also be used natively to pay for slow cloud computing services". They just want the most secure banking/payments system, which is Bitcoin.
Banking system doesn't need bitcoin any more than it needs cancer. The banks handle fiat, why in the world would they support something that's openly anti-bank & anti-fiat?
What are you thinking?
Re ETH being Turing complete: It's a nice gimmick, even "The DAO" is up 18%, and you need ETH to buy that, so DIY demand -- closest to a closed-loop economy crypto ever got.
Vitalik's a clever guy.