Japanese Electronic Dictionary (Casio XD-G9850)

When I was working in Japan, I took the opportunity to buy a Japanese Electronic dictionary (電子辞書, or denshi jisho). I went to the BIC Camera store in Akihabara, and bought a Casio EX-word dataplus 10 model XD-G9850 denshi jisho, which includes specialised dictionaries for Maths and Science. Why Use a Dedicated Dictionary? Why use a dedicated japanese dictionary instead of an app on a smart phone?…