xfs supports larger file systems than ext4 and can not be re-sized smaller (partitions). This works well on servers that usually need to have larger file systems than workstations and are far more likely to re-size partitions larger than shrink them. Workstations will typically require more flexibility with partition re-sizing and usually don't need to support very large file systems - ext4 works well in this scenario.
I think at this stage maintaining ext4 for Workstation and xfs for Server is a good compromise - besides, you can always change from the default options during installation if they don't suit your needs.