OK I guess I’m going to go against the deluge of comments here; And give an appreciable reason instead of denigrating those who might choose this. The context, though, I am British. I grew up in Britain. I went to British school. I can’t speak universally about my experience, (even within all of Britain), because it’s my experience which is in one small area of the country. However, school, for me, was by far the sin…
The kind of school you went to sounds very different from the grammar school that my working-class father went to in the 1960s and that helped him escape a life of asbestos-breathing drudgery in moribund shipyards.
They were created to provide a pathway to the middle class for bright children from working class families. But the entrance exam was heavily biased in favour of children from middle class backgrounds.
Famously the first 11+ tests had questions like "Name the various types of servants in a household and what they do".
In later years, getting out of school tuition was the main way to prep for the 11+, which put grammar schools financially out of reach for a lot of working class families. It had basically become a parallel state funded education system for the middle class.