Or Mr. Leslie.
Discovery didn't invent seat fillers.
How very dare you. That man is the only Starfleet redshirt to be killed by a gaseous anomaly and live. He was one third lanthanite, one third Illyrian, one third human, and one third Q. He is a living legend, not a seat filler.
Jeannie Malone was a seat filler, admittedly. She often silently manned the engineering station but her big moment was giving Kirk poisoned coffee.