Yes, I am aware that Seagate is pushing the 6TB Air (maybe they really should call it that..haha) since the CEO promised it in the last investor call.
He is used in many environments for HDD production (seal checks, etc..) and lots of it is used for assisted servo track writing. Not everywhere and not by everyone but the companies know the price, availability and handling of this gas very well.
Yes, the He drives are supposed to be overall quieter. The air turbulence inside drive which generates the majority of the noise floor just isn't there, He is so much lighter. However you might hear icky pure tones better or more distinct. Anyway, acoustics should not be a problem and a benefit that comes for free. I don't know the design exactly, but the 2nd cover welded on the top gives some extra protection as well.
Most interesting for me is the long term reliability of these drives. And not just that He will leak out slowly.
As for the HDD industry, I think it is great such technology is finally applied and actual available drives exist, it is a bold step for them to go He.
Ad for the storage industry, we will see ow they will be able to address the clould's 'cold storage' demand. Cheap, slow, power saving, huge capacities. He drives are certainly in the opposite direction.