We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
if noise is your primary concern, don't pick exos or the WD DC HC series, they're data center/enterprise hard drives and those guys don't care about noisy drives or heat and they use crazy loud fans so you wouldn't hear the drives anyway.
your 12tb is 5400rpm, when you go bigger they start using 7200rpm drives and they're typically louder but not always. 5400rpm is usually quieter and cooler running.
I have a 14 TB Exo and it sounds like a muffled popcorn bag cooking in my Fractal R5, which has decent sound dampening.