I agree on the concept, however we often encounter limitations that prevent it. For example we are a collaboration partner, we deploy and maintain a lot of collaboration virtual machines which we are unable to backup using the VMware snapshot feature as it is not supported and causes performance issues.

http://docwiki.cisco.com/wiki/Unified_Communications_VMware_Requirements#VMware_Feature_Support_for_Unified_Communications_8.0.282.29_through_10.0