Carrier speed mattered because flying operations pulled a ship away from the rest of a fast task group. A carrier had to turn into the wind to launch or recover aircraft, then regain its position with capital ships that continued along their operational track. Joffre's margin over the Dunkerque class might have been workable, while its smaller margin over the Richelieus would have constrained the whole group. France also needed anti-surface and anti-submarine forces across a geographically dispersed empire, and British carriers filled part of that missing role when war came.
Notable Point · 1:06:39-1:11:00
Fast carriers, global commitments, and task groups
A French carrier needed enough speed to conduct flying operations with capital ships and enough reach to support anti-surface, anti-submarine, and Far Eastern commitments.