the power-on power-off cycling is more damaging than just spinning constantly. thats why WD green were(/are?) shitty on linux which synced the fs just after the idle mechanism of the disk kicked in, causing the disk to spin up again.
https://support.wdc.com/knowledgebase/answer.aspx?ID=5357
server disks are designed to be always-spinning. i've had refurbished server hard drives which were in use for years and continued to work for a long time.
in the end it's probably more the difference between consumer and enterprise hardware.