After completion of the associated quest, if you have unlocked the entire Hub track, this item can be retrieved from the Quest Item Storage chest at the Quest Point Caravan if lost or destroyed. Otherwise, a new one can be obtained from Moldark.
The only reason to keep this item is to access Zamorak's hideout and the Stalker Dungeon that is attached to it. Beyond this, there is no need to keep this item after the quest has been completed. As such, it can be destroyed or kept as you desire.