Until you learn attain sufficient music literacy, every piece you learn is an island.
One of the biggest gifts music literacy can give you is the gift of perspective. That is, the ability to recognize common characteristics from one piece to the next.
Imagine you are an explorer in the wilderness. You are an explore with zero knowledge of botany, zoology, or geology. If you should set out on a sailing voyage, every island you came across would be new, with no experience you could apply to studying the nature on the island.
With knowledge of flora, fauna, rocks and minerals, you might quickly discover that the islands you are exploring are part of an archipelago, sharing many similar traits and patterns. Your background knowledge would both make the exploration far more efficient and more productive – yielding more knowledge about the places you explore.
That’s the thing. You are more efficient and more productive when you acquire more music literacy.