In addition to what sibling commenters have said, I think part of the issue is friction and need. Out of the hundreds of merchants I transact with, probably only a handful accept cryptocurrencies, and that is in addition to "conventional" payment methods. So why would I bother?
Beyond that, paying with a cryptocurrency requires extra technical effort that many people don't have or don't want to deal with. Using an exchange to switch between fiat and cryptocurrency is an extra step that adds friction (and many of these exchanges end up embroiled in scandal and/or get shut down, making it hard for people to trust the extant players). And the sheer number of choices of what coin to use also muddies the waters for many people. Bitcoin is obviously well known, but transactions are slow (or are on a lightning network, which requires understanding more concepts and jargon) and expensive.
Then there's volatility: Bitcoin lost nearly 3% of its value (against USD) today. I certainly wouldn't trust that to keep money in as a stable store, like a checking or savings account analogue. Sure, you can go for things like USDC (and you probably should!), but the concept of a stablecoin is another concept to learn, and then you have to figure out how to get them and transact with them. A quick web search for "pay with USDC" shows quite a few options, and your average person isn't going to know what to do there.
Also consider that this article was about bank transfers, and bank transfers alone. In the US, for example, we get around the annoyance of bank transfers with credit and debit cards, and payment apps like Zelle, Venmo, and Cash App. Ultimately there's very little actual need for cryptocurrencies.
Certainly one big area is international transfers, but most people (in the US, at least) either don't need to do them at all, or have other options. For payments to many non-US merchants, I can still use my US-issued credit card. International person-to-person payments are the main pain point, and I expect some people do use cryptocurrencies for this. Others stick with the older-school methods like Western Union.
When traveling internationally, I used to withdraw local currency (using my US-bank-issued debit card) at the destination airport, and then mostly pay with cash. These days I find that most places I travel will accept US credit cards in many places, so I essentially pay the same way I pay at home, while being sure to use a card that doesn't impose foreign transaction fees. Certainly there are countries where US credit cards aren't all that useful, but I think the point is that those places are likely a minority when it comes to where most Americans might travel, not to mention that most Americans rarely or never leave the US in the first place -- many don't even have passports!