The advantages of cluster-specific rules different from cluster-external rules over having no differentiation is both significant and win-win for application deployers as well as their customers. Consider the use case where the analysis over logs need to have proprietary logic or have query hints or annotations that can help product support but need not be part of the queries from customers. Taking this to another extreme, let us say the cluster deployed application would like to have competitive advantage over the marketplace log store capabilities outside the cluster. These use cases broaden the horizon over the storage of logs especially when the application is a storage product.
Let us take another use case where the cluster specific solution provides an interim remediation for disaster recovery especially when the points of failure are external services. In such a failure case, the user will remain blind to the operations of the cluster since the cluster external log services are not giving visibility into the latest log entries. Similarly, external network connection may have been taken for granted while the administrator may find it easy to retrieve the logs from the cluster and send it offline for analysis by remote teams. The dual possibility of internal and external provides benefits for many other product perspectives.
The logs generated in cluster are usually saved on persistent volumes which are available between restarts. If the application prefers external only logging, then any internal storage for this purpose can be ephemeral.

The dependencies on external log services come with downstream benefits such as api monitoring