Would be good for limited uses.
But man it would have been nice to have had one when I was doing my job in the service. I used to have to take small notes on events happening, for analysis. So I went through tons of notepads of paper in my time there. Having one of these would have saved alot. Take the notes, go to desk, work out the data as needed hit the button, get more notes repeat.
Now I use alot of notebooks as I work through designs and it wouldn't help except maybe as the scratch pad before putting something in a notebook.