Non shielded RAM is subject to bit flipping. Non-ECC always carries this risk in general computing, but the problem is compounded when you run a filesystem like ZFS which uses memory as a significant storage element for write cache.
If it would hugely impact your life if a bit were flipped from a 0 to 1 in your stored data - say you make videos or store your bitcoin wallet key on your NAS - you are running a risk not using ECC.
You may not have had issues or ever have issues with non-ECC. Your car may never be stolen if you leave the keys in either, but it's not a good risk proposition for most people.
If it would hugely impact your life if a bit were flipped from a 0 to 1 in your stored data - say you make videos or store your bitcoin wallet key on your NAS - you are running a risk not using ECC.
You may not have had issues or ever have issues with non-ECC. Your car may never be stolen if you leave the keys in either, but it's not a good risk proposition for most people.