What a group can define up front
A group defines the batch title, batch description, item count, personal-or-team scope, starting visibility, optional immediate activation, and the shared defaults for item title, item description, status message, and external link.
That is why the group form is best for campaigns, classroom kits, club drops, event giveaways, or any other situation where several items should begin from the same baseline.
What a group does not replace
A group does not turn several trackables into one record. Each item still has its own codes, its own route history, its own ownership state, and its own future edits after activation.
If an item later needs its own story, images, or different public link, that should happen on the individual trackable instead of trying to force every item in the batch to stay identical forever.