The difference between teaching children's songs and folk children's songs

The biggest difference between folk children's songs and children's songs created by writers is the arrangement of music.

Folk songs and children's songs, they generally think of cattle, but they are not outstanding in music.

When the screenwriter makes a children's song, he will consider what key is better for this song.

Is there any way to make the melody of this song more beautiful

This should be the biggest difference between folk nursery rhymes and nursery rhymes written by writers.