I disagree and would argue that this is nonsense. You're viewing Bitcoin as a currency. Do not people store their own money in banks as life savings? Is this not one of the aspects of a real currency? The difference here is that you're your own bank and thus responsible for your own money. Obviously you should not just be saving, but also using Bitcoin. However, there is nothing wrong with storing.
You could always do both. Put some round amount in cold wallet and actively use the rest. Biggest problem is not many people have any sort Bitcoin earnings, that's currently the biggest obstacle in BTC adoption and it's use as currency.
I agree, but I'd say it is among the biggest obstacles (not the sole one) in adoption. There needs to be more ways to get paid in Bitcoin.