As Howard says, create a process to verify backups at the very least, bi-weekly. We have ours set to 2 and we are running a Galera cluster, we have not had any issues in the past year. We also used 2 even before we moved to a Galera Cluster and did not have any issues since I have been working here, that is since 2007.
I would say use it if you are satisfied with the performance. In the event that MySQL fails and you have a Slave running you would lose those few seconds of data while if you didn't have the slave you would lose as much data after your most recent backup.