There are many posts about these Seagate Expansion Desktop Drive's having Barracudas inside, and the datasheet tells us a quite low number regarding "power on hours per year": https://www.seagate.com/content/dam/seagate/en/content-fragments/products/datasheets/barracuda-3-5-hdd/barracuda-3-5-hddDS2131-3-US2411-en_US.pdf
I'm considering to buy the 24TB model, and use it as a genuine external drive, no plans for shucking. That will be ST24000DM001 I guess.
Now about the 2400 hours / 100 days... I honestly dunno. Likely the HDD won't be up and running for 2400 hours, but I'm more worried about why this limitation exists in the first place.
Are Barracudas just low quality drives, and therefore better to avoid them? I'd pay then more for a WD external, but would like to understand what's going on here.