Needed by MDB containers.
An MDB creates several connections during its deployment. If using a load-balancing clustered ConnectionFactory, they'll end up on different cluster nodes, which is precisely what the MDB container doesn't need. On the other hand, if using a "dumb" non-clustered ConnectionFactory, the MDB container doesn't benefit from the cluster failover capabilities. A clustered ConnectionFactory with no load balancing, but failover capabilities is needed.