> when they do happen they aren't likely to be a big deal.
But with more sensitive data it might matter to you. Ram can go bad like hdds can, and without ecc you have no chance of telling. Zfs won't help you here if the bit flip happens in the page cache. The file will corrupt in ram and Zfs will happily calculate a checksum for that corrupted data and store that alongside the file.
I'd happened to archive the files to CD-R's incidentally. I was able to compare those archived files to the ones that remained on my file server. There were bit flips randomly in some of the files.
After that happened I started hashing all of my files and comparing hashes when I migrate files during server upgrades. Prior to using ZFS I also periodically verified file hashes with a cheapo Perl script.
You can Google more, but, I'll just leave this from the first page of the openZFS manual:
Misinformation has been circulated that ZFS data integrity features are somehow worse than those of other filesystems when ECC RAM is not used. This is not the case: all software needs ECC RAM for reliable operation and ZFS is no different from any other filesystem in that regard.[1]
I agree that ECC is a damn good idea - I use it on my home server. But, my lappy (i5 thinkpad) doesn't have it.
There aren't that many cases where it actually matters.