This is a big question. If missions don’t happen, a Gentile like me never hears the Good News. Specifically, it has broadened my understanding of the Lord and His work around the world. My faith grows each time I am on a trip as I leave my comfort zone and allow God to use me.
In the early 2000’s I had that opportunity to help lead several mission trips to a basically unreached people group in Ecuador. It was amazing to see people receive the Lord, experience miracles, etc. The presence of the Lord was so powerful among them and they were so eager to hear and receive.