I still use an HP-12C financial calculator, although somewhat sporadically now. It used to be an extremely useful companion when I worked with loan processing systems some years ago.
> Somehow for me using a calculator like that, rather than having to use screen space, or a phone …. Makes my workflow better.
Indeed. I can't explain why, but I feel the same. I wonder about the possible reasons. The tactile response? The focus (the device has a sole purpose)?