The Hologuise allows the user to disguise themeselves as Captain Qwark, which Ratchet and Clank used to infiltrate the Deplanetiser's security systems. Since Qwark had turned against the Galactic Rangers and sided with Drek and Dr. Nefarious, the warbots and Blarg aboard the Deplanetiser trusted Qwark, so, by disguising as Qwark, Ratchet and Clank got past the security systems by fooling the warbots into deactivating the force fields.