It actually seems like a good idea but I wonder if people back then really had the time to fool with it rather than just writing down a list on paper.
I see this as being helpful in situations where you’re headed out to the store, and either nobody’s home to ask what’s needed/wanted, and (in this age of smartphones) they’re not immediately available to respond.
The great thing is, in this age of smartphones, you can just snap a photo instead of fooling with the tabs themselves or with pen and paper.
ETA: I just remembered that when I was young (late 1960s), we had a little chalkboard and a piece of chalk on a string hung in the kitchen, a la the Brady Bunch, except ours had a nice little wooden frame.
