> the reality of disenfranchisement faced by the elderly, immigrants, the homeless and the unbanked for whom cash remains a lifeline

On the one hand the disenfranchisement is real. On the other hand many of these people are able to learn lots of new technologies if properly incentivized. It's generally an opt-out of society that's enabled by workarounds being available.

Should we forego on convenience because we have a bunch of naysayers?

Forget about cash, try living life in de Randstad area without a smartphone and half a dozen apps setup, configured and tuned for you life. It's definitely possible, but you will be living at a different level of velocity than if you have all the tools at your disposal.