Mine would be creating pen and paper ciphers for my made up secret communication needs.
I’m old enough to remember when shorthand was a required course for women in secretarial schools. I always though it was black magic and very cool.
In my 60’s. According to Internet sources, shorthand was taught in schools until the 1990’s. It’s likely that shorthand use declined as PCs became common in offices.
I think it was still taught to business students up until the mid-90’s in my country. That’s also how I got my hands on an old Gregg shorthand textbook. That, and typing (via a typewriter) which was the one I learned when I was in high school.
Had I had a choice, I would have chosen to learn shorthand instead.