Snapshot its great to create clones of your object along your animation. Its also a way to visualize your object animation as mesh, that its present from the first frame, and you can drive multiple fx from this.
The snapshot problem is that is destructive, and doesnt allow for flexible approaches, having snapshoot as modifier will allow for much more interesting effects.
Clovis already did a very cool plugin that showcase how much more things we can do with this element as a modifier.
https://vimeo.com/101340988
