VMware snapshots are commonly used to put a VM into a journaling mode to make sure any new changes are captured in case they need to be reverted.  Upgrades, patches etc are the normal use case.  The problem is they cannot be scheduled and they can be wieldy to manage.  SAN based snapshots utilize the SAN hardware to efficiently capture point in time data on the disk.  Until now the two were usually not aware of each other.  Now we can put the VM into snapshot mode to get all the benifits you see there of the sync driver, memory dump etc and then take a SAN based snapshot and get all the benifits of that including scheduling, grouping etc.

-Will