@skyblond ZFS manages the storage medium and use of it. If there is a corruption, it could destroy data on a drive or not recognize it.
I think it would be worth the compromise to use ECC. It could work without ECC ram but in a NAS I assume the Error rate would be higher. The uptime would see more potential errors from the time alone, not to mention the heat and other factors.
Nothing is ever a problem until it becomes problematic.
@AmpBenzScientist Thanks for the answer! ECC, to me, feels more like an insurance. Generally you don't need it, but when you do, you will be glad to have one. With my old NAS, I do have DDR3 ECC RAM, which is fairly cheap nowadays.
(BTW my old nas has dual E5 2695v3, which I can't run it 7x24 because it will literally blow up the electric bill and the single core performance is not that good)
However, for my new NAS, I decide to go with DDR5 and DDR5 ECC requires at least workstation hardware... And it's not cheap (not to mention that I'm in China and brands like ASUS don't sell workstation motherboard to individual consumers). So I guess for now I'll stick with non-ECC and do my best with backups.