Prometheus-mongodb-exporter question

I am currently exploring monitoring with Prometheus and Grafana. I installed Prometheus, Grafana, MongoDB, and MongoDB Exporter using Helm. When looking for ways to monitor MongoDB, I realized that I can still observe MongoDB metrics without installing MongoDB Exporter. I see that the MongoDB Exporter image has already been written in the values.yaml file of MongoDB. Is it really necessary to install MongoDB Exporter when wanting to monitor MongoDB with Helm?