How did working as a song plugger help George Gershwin develop as a musician?

Working as a song plugger for the Jerome Remick music-publishing company was a pivotal period in George Gershwin’s early career. Although he later referred to the experience as "plugger’s purgatory" due to the long hours spent playing tunes for potential customers in Tin Pan Alley, the role was instrumental in his development as a musician.1

The constant demand to demonstrate sheet music significantly improved Gershwin's technical abilities, specifically enhancing his dexterity at the piano. Furthermore, the job required him to constantly adapt and perform various pieces, which greatly increased his skills in improvisation and transposing. These competencies, gained while still in his teens, helped establish his reputation as one of the most talented pianists in the New York area, eventually leading to work as an accompanist and a rehearsal pianist for Broadway musicals.12