I think i understand how the japanese keyboard works

Ok so basically I’ve been learning Japanese for the past couple of months because I like lots of things related to them and their culture (anime, music, their monuments and nature) and to help me learn the language through duolingo I downloaded the Japanese package onto my keyboard……

I found it very weird at first because it was only a basic Nokia number grid with the hiragana in all of them but after some learning of the characters, I finally get it why it was made like this!!!

Basically I think the hiragana are divided by their initial sound, like there’s one space for only vowels like あえいおう ,then for the k’s: かけきこく then the S sounds: させしそす and so on…..

Was this made on purpose or maybe to help writting and how are physical keyboards on Japan? Do they type in romanji or is it a keyboard with the hiragana itself?? I’m curious about it!!!