After installing loki/grafana I see there are two loki services created, one of them a loki-headless. Because I started loki with the serviceMonitor.enabled=true I also see a service monitor is created to have Prometheus scrap the loki-headless.
So why are there two services pointing to the same pods?
I think the assumption is that you might b using the Prometheus operator for Kubernetes. That operator manages config that mainly discovers ServiceMonitor resources and as the resource name suggests, you will need a Service resource for it to monitor (if that makes sense).