The idea that the RN was significant has been accepted since at least 1974 when the BoB was wargamed at Sandhurst for a reason I forget.
The key point is that while the LW was poorly equipped for sinking capital ships, it was far better to ensure that they didn't have the chance to say 'Ah-ha! Now to see what the Stuka can do against ships!' and get some practice in. Those arguing that the Luftwaffe would never have sunk any ships seem to forget that Channel convoys (admittedly not capital ships) ran into serious bother, and that air attack accounted for a number of destroyers. Reduce the RN's non-capital ship capability and life might get interesting. It might not, but again - better that the Luftwaffe failed to get the opportunity to see whether or not it could overcome the RN, IMO...