Why cruiser forces still needed Tribal destroyers

How did Tribal-class destroyers work with light and heavy cruisers when the cruisers already provided strong gunfire?

They screened the cruiser force, countered close destroyer threats, and provided the fighting cover needed to get the cruisers safely out of danger.

Force K in the Mediterranean included Tribals alongside Arethusa-class cruisers in an offensive raiding force. The cruiser sweep into the Adriatic associated with the Taranto operation likewise combined three cruisers with two Tribals. The destroyers remained useful even though the cruisers carried heavier guns. They screened the force, fought off destroyer threats, and helped ensure the more valuable cruisers could disengage and return.