I personally doubt that the transition to a digital cash will happen anytime soon as there are lots of factors to be considered.
Due to the disparity among developed, developing, and underdeveloped countries, the latter two suffers from technological deficiencies and innovation as each country has their own set of priorities. In addition, the shift to a digital cash system implies that the platform used would be secure and tamper-proof in order to avoid loss of cash. Lastly, the presence of physical cash has been in existence since time immemorial.
The barter system of transaction slowly transformed to using coins which represent cash in the society. Despite the convenience of having digital cash to purchase goods, a shift to this kind of system will leave other countries behind.
It is necessary to clearly separate the concepts of "transition to digital money" and "full transition to digital money". It is safe to say that in some countries, the transition to digital money has mostly already occurred, and some countries with a small population may even announce a full transition to digital money. The world is heterogeneous, so a complete transition to digital money in the near future does not make any sense. Poor countries may not have enough resources to do so, and large countries cannot afford to do so because of their size and infrastructure security.