Why Britain did not need a Tone-style hybrid cruiser

Would a Tone-style cruiser-seaplane hybrid have suited Britain or the United States?

No; navies able to build enough specialized ships would gain more from separate cruisers and aviation-support vessels.

Japan's shortage of carrier capacity created a reason to accept the Tone design's compromises. The resulting ship was an unsatisfactory choice for ordinary cruiser work and lacked the capability of a dedicated aviation ship. Britain and the United States could build enough separate ships to perform those duties. For them, specialized cruisers and aviation-support vessels offered a more useful allocation of construction capacity.