Plugin snapshots are great if you just want to store and recall the settings of a single plugin. More often, you want to store multiple, complete setups within the same project.
This is what Global Snapshots do.
When recalling a global snapshot you usually want to filter out specific elements that you do not want to recall. This filter is set by clicking on the F button on each snapshot. Usually you do not want to recall the audio patch and window layout for each song. In that case, you can filter out the audio patch and save the filter as the default filter for new cues by clicking the settings button in the filter editor.
Generally, try to filter out as much as you can from the global snapshots to make them recall faster.