Well, I think the conclusion of the survey is simply wrong. Cryptocurrencies are already a major asset class, currently about $2.57 Trillion. That puts them well ahead of the silver market cap, which is already an important market, the thing is that if we want to compare them with the total stock market or with the real estate market, for example, it seems to be small, but of course cryptocurrencies are already an important asset class today and it is not only seen by the numbers but also because they are increasingly occupying more and more space in the financial news.
On the other hand, I don't believe that they will become a payment method. Maybe one cryptocurrency out of the tens of thousands that exist will do so, but they are mainly investments, not means of exchange, and with CBDCs it will be even more difficult for them to become a means of exchange.