Not really. Aircraft keep subs submerged because subs are very vulnerable to all types of attacks on the surface if they're spotted, and aircraft are good at spotting submarines. Blimps are, in principle at least, more effective at this per aircraft than other types because they have a much longer endurance than other types of aircraft, therefore they are more effective in preventing attacks (because submarines are too slow underwater to catch all but the most sluggish ships) than other types of aircraft. The point is that you might be able to slice things up so that airships use less of some resources than heavy bombers do. Use crappy surplus engines that wouldn't work for a bomber but are fine for a wallowing blimp. Use older or younger personnel than in a bomber squadron. A gondola might use less aluminum than a bomber, because it doesn't have wings or various other bits and bobs. Therefore, Coastal Command or the equivalent can wrangle a few airships out in the political process when it might not be able to get an equivalently effective number of bombers, or for that matter any bombers. It would hardly be the first time that some less than ideal compromise came out of internal politics. And what was the rate for conventional aircraft? Without that information, the statistics you've provided are completely useless.