Having our naval aviation the capability to fire Hellfire missile etc is good to support amphibious ops, but it should be fired from Attack helos rather than ASuW helos.
Our marines doesn't have their own air unit.
we don't need specialized attack helo for the navy, the army could hitchhike whatever platform the navy provide. unless you're a superpower there's no need for exclusive all navy wing onboard a warship.
The Australians operate their army Tiger attack chopper from their Canberra LHD, the JASDF will operate their F-35B's from the Izumo light carrier. I don't see why the navy wouldn't lend their deck space to the army if the mission objective needed them to do so.
Funding is and always remain the major issue here, the navy must choose which capability it wants with their share of the budget pie. The navy already stated they wanted ASuW capable chopper and I don't think its with some quasi light attack capability with Hellfire, and I could already understand why.
air power had been the deciding factor of naval combat since WW2, that is the first time navies fought each other from beyond the horizon and maybe the last time naval warship faces off Jutland style. It's always been the navy with larger and more adequate air power than won any sort of naval battle since then. You name it, Falklands, Gulf of Sidra, Praying Mantis etc.
The fact is that we had been neglecting the use of naval airpower as a mean to sink enemy warships and the navy realized that. The navy are trying to fix this by planning to add larger more capable helicopters with ASuW capability because frankly such is the only realistic option for the navy to expand and develop its naval airpower. Navy operating fighter jets is clearly out of option here because it will cause some very likely "konflik kepentingan" with the air force.
By focusing on ASuW (with AShM) we could maximize the potential of our navy, instead of investing in multiple platform (attack helicopters) like you mentioned. off course with budget in mind.
But again this is just my opinion.