My wife is woefully low tech and mathematically challenged. How she ever got a masters Library "Science" still leaves me scratching my head. As computers became more and more present in libraries she struggled. Through sheer determination and repetition she managed to keep up.
As a consequence and considering I'm most likely to go first I have set things up both electronically and on paper. The kids and I can bring up the spreadsheets and know our entire financial situation at a glance.
On the other hand, my wife would be lost. So I still have all of our bills and other financial correspondence delivered in paper form. With a checkbook and stamps she can run the financial side of her life.
The only problem with this is that just about every company we do business with constantly tries to switch to only electronic communication. They now, from time to time, send emails saying that since we have used electronic payments they are, without prior consent, switching to electronic billing. It takes constant monitoring to keep things coming by snail mail.
My point of this ramble is that she still writes checks or pays cash for things. With fewer and fewer establishments accepting checks she is, more and more, becoming a cash only customer. It's actually somewhat entertaining to watch the conduction of business between my wife and say a grocery store clerk.
Given a check most clerks stumble on the proper store procedures. I've seen a few call the manager for help. Cash can be even more entertaining as I was two "adults" struggle to determine proper change. Again, managers have been called.