America-Desu would be like you're answering somebody.like this
Person 1 : What is a place where people speak English? (In Japanese)
Person 2 : America-Desu. (That is the polite way to say it.)
I thought Americas was the whole continent? Sorry if I'm wrong, English is my 2nd language.
Es más facil aprenderlo desde el español xd pero me conformo con esto :v
Historical reasons. Nowadays, hiragana is used for japanese an and katakana for loanwords and some other things.
I notice a few people are confused on why the Japanese would refer to the US as simply the continent name, and I assume this is purely out of ease because saying US is a bit more difficult than saying アメリカ. They have a different word for North and South America.
Also plays in to a lot of the world calling US Citizens Americans, which the Japanese do as well ＊アメリカ人＊ pretty much meaning Man from America if I understand it properly.
This article is fairly interesting.
Hiragana are used to write words of japanese origin and particles like は, の and such, Katakana are used to write words of foreign origin.