Why do you think a composer would need enharmonic notes to compose music

Two notes are enharmonic if they sound the same on a piano but are named and written differently. ... So a composer may very well prefer to write an E sharp, because that makes the note's place in the harmonies of a piece more clear to the performer.

Because it provides the option of writing a scale using either sharps or flats. Since it's best to use only one type of accidental in each composition, this option makes some key changes easier to compose and read.

Explanation:

Enharmonic equivalents can also be used to improve the readability of a line of music. For example, a sequence of notes is more easily read as "ascending" or "descending" if the noteheads are on different positions on the staff. Doing so may also reduce the number of accidentals that must be used.

a chromatic scale uses the twelve tones of the octave, while a regular scale only uses eight, or seven different notes (as the first note is played twice)