If students are learning to play western classical instruments, then they will learn to read staff notation. But if they're learning uilleann pipes, or tabla it's arguably less important.
Apparently, it will soon be possible to get an A in GCSE literature without being able to read or write a word of English. According some passing twonk, "If students are learning about western classical literature, then they will learn to read English. But if they're reading Brazilian or Iranian literature, it's arguably less important.