Why is pepsin secreted as pepsinogen rather than as active pepsin inside gastric glands?

Pepsinogen is less energy expensive to produce than pepsin and therefore secreted to conserve ATP inside gland cells

Pepsinogen acts as a hormone to stimulate mucus production rather than as an enzyme, and is later repurposed into pepsin by liver enzymes

To prevent autodigestion of the gastric gland proteins and cells; pepsinogen is inactive until converted to pepsin by low pH in the stomach lumen

Pepsinogen functions as an acid buffer inside glands and only becomes enzymatically active when neutral pH is reached, which never happens in the lumen