With 48 aircraft, you can sustain a 24-aircraft carrier wing for a sensible length of time. If your regular carrier strength is lower than that you might be able to provide some land-based operational capability as well. Under 48 aircraft, however, you can't even maintain a fig-leaf pretense that the GR4 is being replaced.
This is what happens when you select an aircraft that costs 80 per cent as much as an F-22.