Why torpedo-boat leaders were destroyers

Why did navies not build torpedo-boat leaders instead of destroyers?

A torpedo-boat leader with enough guns to hunt enemy torpedo craft was effectively a destroyer in this period.

Torpedo-boat leaders were destroyers in the period under discussion. The displacement difference between a torpedo boat and a destroyer was often small, so the distinction depended mainly on guns and the ability to engage enemy counterparts. Destroyers soon developed from hunting torpedo boats to fighting other destroyers, a change linked to the large numbers being built. A ship capable of defeating a rival destroyer could probably also defeat a torpedo boat.