Duvets are absolutely the norm in the uk
So much so, that the first time I went to the US, the first thing I asked in my hotel was 'where is the duvet??'

yuk- Horrible nasty sheets and blankets- especially made from polyester or other static charge holding materials....
Find them too thin, too clingy, and too hot.
Plus there are too many of them and some berk has always tucked them in the end of the bed.