The rendering on that 42s is close enough that I can almost feel the buttons. Never thought I'd describe a calculator as sensual, but HP's of that era had such a distinct look and feel.
This is a great find. I used a 42S heavily through high school and college. I was surprised at how some of the muscle memory of how I did certain things came back. Seeing the dot matrix answer after doing some calculations brought back the feeling of being bored in math class, when I would just play with all the functions and write little programs. I didn't have a phone or even a laptop to turn to in those days.
Even now though, it will be useful to do calculations in RPN. Even the ability to swap X and Y, and store intermediate results in order to avoid parentheses or M buttons is nice.