It matters to the person.
Some look at a sheet of music and throw it in the air...others look at it and hear it..
Some don't want to learn some do.
It is a form of communication. You can choose to use it or not. If you use it you can
communicate with others that use it. If you don't read or write then others that do cannot
communicate with you with that form.
Some people can talk and hear but can't read or write. It limits them to what they say or hear.
Of course there are no guarantees for being a better musician or benefitting in any way
from learning to read and write music....just like there is no guarantee that somebody
that can read or write understands a word.
Learning is a desire and an ability. Some have both, some don't.