But just because it is commonly misapplied and misperceived doesn't mean musical literacy is a bad thing. It has many benefits, just as regular literacy does - but it doesn't have a monopoly on expression or storytelling any more than prose, and indeed there can be bad writing and excessive concern over grammar as well. And, just as anyone who does live poetry readings often memorizes the words, actual musical performance should not heavily lean on the written copy - even in an orchestra, players should know the music well enough to also keep the conductor in their vision.
Lots of benefits of musical literacy are pretty similar to regular reading and writing - you can explore ideas from past creators, serialize and share your own ideas more broadly, and more consistently track something that you're making subtle changes to over time (ink on paper doesn't shift or falter as our memory does). But one non-obvious benefit - it's also critical to coordination for larger ensembles.
Musical expression is a joy, and a very individualistic thing. But the creations of an orchestra or similar ensemble require intense coordination - I believe this doesn't rob them of value, but rather adds another dimension to them. It's not unlike the difference between making a solo or small group project versus trying to build something as a company with more employees. People have to align on the basics so, as a group, they can achieve larger things.
A mantra I have for this is "Play the Indicated Pitches at the Indicated Rhythms", which I explain more here - https://gallant.dev/posts/play-the-indicated-pitches-at-the-...