I don’t know very much about music, but one thing I’m sure of: there’s no point in doing a cover of a song that’s exactly the same as the original.
The best covers I’ve heard take a great piece of music and try something different with it. The songwriter comes at the same melody from a different angle (or in this case, key, I guess?) creating a new work that shares DNA with the original, but succeeds on its own. Last year Ryan Adams famously covered an entire Taylor Swift pop album with his own unique style, but I also like Damhnait Doyle’s haunted-music-box take on “I Want You to Want Me” or Yael Naïm’s surprisingly unsettling rendition of Britney Spears’ “Toxic.” Covers are not actually about being better or worse than the original. Good covers become their own unique thing.
And movies are often the same.