Western Music grew out of the seedbed of complex melodies preserved by the assiduous efforts of the Monks of Solesmes. Learning these pieces helps give new musicians a standing with the greats.
Learning Latin was the basis of all education in the Middle Ages. All the textbooks and learned material was in the Latin language to facilitate learning across many different nationalities.
This is the music that many, many saints in heaven sang. Learning chant now can give you a headstart on singing a Te Deum with St Francis of Assisi when you reach the pearly gates.