Nowadays we live in a world that is becoming more and more interconnected, such that it has created, pushed to the digitizing trend. For example, payment methods: electronic transactions have existed for years, and for even longer magnetic cards. Since 2008 the Crypto have been added, after the launch of Bitcoin.
Some examples that talk about this trend (research, discussions, criticism, etc.):
https://www.wexinc.com/insights/blog/inside-wex/4-reasons-why-the-digitization-of-payments-is-imminent/
https://www.imf.org/en/News/Articles/2018/05/08/sp050818-digitization-of-money-and-finance-challenges-and-opportunities
https://www.nber.org/papers/w26300
https://www.researchtrend.net/ijet/pdf/Effect%20of%20Digitalization%20on%20the%20Competitiveness%20of%20Money%20Transfer%20Operators%20in%20the%20National%20Payment%20System%20Vladimir%20Vyatcheslavovich%20Kuznetsov%201586j11.pdf
https://www.slideshare.net/raghurx/digitalization-in-banking-sector
https://merchant.razer.com/v3/blog/the-benefits-of-using-both-method-of-payment/
https://thefinancialbrand.com/68528/top-payment-trends-banking-p2p-digital/
https://www.worldbank.org/en/topic/financialinclusion/publication/digital-financial-inclusion
https://positivemoney.org/publications/digital-cash/
https://www.betterthancash.org/tools-research/toolkits/payments-measurement/focusing-your-measurement/introduction
What I would like to talk about is the tendency to encourage e-money as a unique method of payment, with no alternative. Thinking of aiming exclusively at digitalization, at electronic money, as if they were to become the only means of payment while cash has to be "abandoned", - I dare say discouraged -, would be a great risk, also for the freedom of the individual, of the citizen.
Imagine that a payment service (Visa, PayPal, etc.), POS services, suffered a failure of several days. If during those days you have no liquidity because you decided to rely on online accounts, there would be big problems.
Since Bitcoin was released in 2008, the world has known a new means of payment, able to function without relying on decentralized bodies; and therefore, even in anonymity (for various Crypto, not entirely; even though some Crypto's have been tried: Zcash, Monero, Komodo). To this end, wallets, both hot and cold, have been developed to allow anyone to participate in the new currency market - the Crypto market. However, these software also have advantages and disadvantages.
If we talk about hot wallets, we may be subject to various attacks (if you are a trader, you "have to" run it, since you stay connected). For cold wallets, the advantage of being safe from online attacks is offset by the disadvantages of being able to suffer the risk of theft or complete loss if your device breaks down.
I don't want to say that we have to "boycott" these instruments: we just have to be careful in using them and take into account their electronic "nature".
The purpose of the speech is to say that it would be wrong to put everything into a means of payment to be used for all transactions. In other words, it would be necessary to follow the principle of diversification (don't put all the eggs in one basket): the loss in some sectors would be compensated by other sectors.
And we go back to the initial speech: to encourage digitalization as much as I can because it is believed that it can mitigate - if not remove - various dangers related to the "offline" world, that of cash and bartering, could even worsen the situation from various points of view (social, economic, political, educational, etc.).
With cash, you know you have something in your hands; you know you have some sort of limited budget for everyday use.
With digitalization, we can take a risk, perhaps worse than cash: having an electronic wallet that could become inaccessible for various reasons (failure, black-out, ...). It is true that cash would not look as good; but, compared to modern electronic media that are "younger", we have a much longer experience of using cash.
In conclusion, I'd like to say something.
The Crypto world is beautiful, fascinating, new (2008 wouldn't be very far away, but in the technological era one would think of placing it in a remote past); but let's not put all the cards on the table. It can become a pastime, a job. Cash should not be despised but seen as an alternative to electronic means and Crypto, if something happens.
