Just like exhaust header length, cylinder head volumes, base and top gaskets thickness, 4 degrees vs flat top pistons etc etc etc, reed stiffness is just another item that can be fine tuned to find a more accurate setup depending on the track and conditions.
If you are in race conditions and trying to win big events, it could help. If it’s just to driver around and/or club race, a well assembled engine with a good carburation will be more than enough, without having to rack your brain around other variables