Many have been asking about a source for the info about the IMF, and I don't think anyone provided it yet (sorry if I missed it), so
here's something I found. It's from summer of this year, and I guess that since it has authors and is in the blog section, it's more like an opinion article rather than an official position of the IMF. But the only thing I could see here is actually quite far from the claim the op makes:
Some countries may be tempted by a shortcut: adopting cryptoassets as national currencies. Many are indeed secure, easy to access, and cheap to transact. We believe, however, that in most cases risks and costs outweigh potential benefits.
As for Economic Confidental, I believe
here's the article from there. Oh, and through info in
this article I think I found the real source, which is an article on IMF blog by the same authors as the one I linked earlier. Here I see the following:
Some emerging markets and developing economies face more immediate and acute risks of currency substitution through crypto assets, the so-called cryptoization. Capital flow management measures will need to be fine-tuned in the face of cryptoization.
But again, I'm not sure that it's not merely a position of these authors, and I see no evidence here being provided to back up the claim.