Is there any benefit to Sync-to-Channel on the AC4490 if the channel is not changed?

The benefit with Sync-to-Channel is that it synchronizes every ConnexLink with the same system ID and channel number in the infrastructure. The downside is that if the main synchronizing server goes down, then the entire infrastructure goes down. Co-locating multiple systems with different system ID and channel numbers is usually a better solution unless the infrastructure synchronization is required.