Pocket electronic dictionaries have been around and not strictly in Casio's wheelhouse but an "era": I used to carry around one made by Besta, a Taiwanese company. What's interesting was their integration with PCMCIA cards for language and dictionary expansion.
Pocket dictionary was (still?) an interesting hackable device in Japan until around 2012. Some uses Windows CE/Linux and can run full Linux desktop by hacking. So some students uses it for general purpose at school. The only electric device that teachers don't mind, and portable device was rare at that time (like PSP), and even have a keyboard.
They are fun. I know my smartphone can do way more but having a device with Encyclopedia Britannica, a dozen dictionaries and more makes it feel like I'm holding a hitchhiker's guide to the galaxy.