Why carriers should rely on cruiser escorts

Would larger treaty carriers benefit from retaining heavy cruiser-calibre guns?

No; 8-inch guns burden flight operations, while a separate cruiser can fight the delaying action and let the carrier escape and launch aircraft.

Large guns add topweight and interfere with the air group while failing to solve the central problem of a carrier caught by surface ships. A separate cruiser escort can delay the attacker while the carrier opens distance and launches aircraft. In the best case, those aircraft return to save the cruiser, but the escort's first duty is to preserve the carrier. That division protects aviation capacity and gives each ship a coherent tactical role.