While by no means an SMHV expert, I have a few thoughts.
Concerning your intent to take snapshots before patches and application installs, SMHV will allow you to create OS and application consistent snapshots. These will ensure that the OS and/or applications running are in a good state that can be restore to should the need arise.
In addition SMHV allows you to catalog the different snapshot(online back-ups) by name, date etc for each VM. This would allow you to keep a list and maintain a list of the different snapshots and patch levels/application install statuses for your VMs.
It further integrates with snapmirror and snapvault if you wanted to keep a second copy in an alternate location on the filer or a secondary filer.
One con I can think of is that to use the restore capabilities to an earlier snapshot of the VM, would require purchase of a SnapRestore license.
Hope this helps.