Well, Amazon does have a global presence, for worse rather than better in my opinion, but I live in Brazil and, as far as I am aware, there isn't really any other decent e-reader brand selling its devices here officially and conversion rates plus taxes would make it really expensive to import anything else, so that could be a reason.

I have an 2016 basic kindle that I use often, it is sideloaded with KOreader (official software didn't support epubs when I bought it) and I mainly use it for non-amazon books through Calibre or cable transfer.