Elaina practiced the incomplete song, and although the music is great in the ears, and how it changes the surroundings while the music is playing, it doesn't change the fact that the song is still in its infancy and is incomplete. This results in music with an effect that can make some sort of intended effect, but can't fully utilize its purpose due to the lack of the necessary components to make it work.
Even Adelaide also noticed the song's missing "oomph" after Elaina mastered the actual sheet of music. Since she knows the music of harmonica a lot since her last life, it is not that hard for her to notice the missing piece the longer she listens on the music.
"I thought this music is a unique one after learning that it was an elf who made this music but after fully listening to it, I just realized that it was incomplete and it's only main use is a regular music piece," Adelaide said to her mother one day when she saw her mother playing the music once again.
