Almost all starships of interstellar civilizations are equipped with a self-destruct feature, which is not about igniting their own ammunition storage but involves inserting an instability inductor within the energy module. Within an extremely short period, this turns the ship's antimatter energy core into a massive antimatter bomb.
The setting of such a feature on interstellar warships is primarily to deal a deadly blow to the enemy in a final battle, employing a strategy of mutual destruction. More importantly, any interstellar warship contains abundant technological intelligence of a civilization, from its construction to its details. Understanding and analysis of such data can lead to a profound comprehension of a civilization, and in some cases, if important technologies fall into enemy hands, they could have severe consequences for the civilization itself.