Why the Royal Navy risked carriers in submarine hunting groups

Why was the Royal Navy willing to risk fleet carriers while hunting submarines early in the Second World War?

Carrier aircraft multiplied the effectiveness of anti-submarine searches, but the Navy lacked enough smaller cruiser-carriers and therefore used fleet carriers for the job.

Exercises had demonstrated the value of aircraft for searching wide areas, forcing submarines to dive, and attacking them on the surface. The Royal Navy therefore saw carrier-led hunting groups as a powerful anti-submarine tool rather than simply misclassifying carriers as cruisers. Treaty tonnage and the lack of enough Hermes-sized cruiser-carriers meant that scarce fleet carriers had to perform a task for which smaller carriers would have been better suited.