"Language & Region" is duplicated in both Basic settings and Advanced Settings>>General
That's currently intentional (it sucks when you set something to a language you don't speak and can't find the menu anymore) 
Maybe I'll remove it from the advanced settings in the future.
what difference does "region" makes , in terms of BTT features? is it purely informational? or does it make a difference for default sites opening (example amazon.de vs amazon.com) ?
it affects things like date formats and decimal styles in some actions