I disagree because we are already using cryptos to buy goods and pay the services. It's already been proven and now it keeps becoming more useful in terms of its function and development. So, I believed that cryptos will be more useful in the coming more years.
I disagree with you too,if something is called as currency then it needs to be used fluently everywhere buying few products at the market section doesn't make bitcoin as currency.Everyone need to start treating bitcoin as a currency if we want the crypto to stay longer.