Great quote!

Your final sentence seems a bit odd in that context though: Churchill's point is that Latin and Greek actually isn't useful at all, so it would follow that it isn't better to do both (i.e. study the classics as well as English), especially as time to learn them would have a huge opportunity cost, e.g. you could use that time to study more English composition instead.

(If you think they're worth learning just for their own sake then that's another matter, but the quote seems to imply that Churchill wouldn't agree.)