I think the issue is here: “I can’t remember reading a good explanation of why.” One can make any number of excuses for why or why not to do things, it really is what you want to do.
I use Windows Core solely for my file storage. I have thought about moving to a solution like TrueNas but didn’t find that as simple as my current solution. I found windows core runs hdsentinel and ssh/iscsi/nfs/samba easily and the uptime is well over 3 years. I block outside access and never do updates. Since I have a mixture of Windows and Linux/BSD/Arm/Apple products in my home the file server is dedicated to file storage and does nothing else. Windows core is stable and always up.
I only use ReFS because I did have corruption with NTFS and it has been super stable. I know people love ZFS, but for me it was an unmitigated shit show of mismatched utilities and documentation, and losing containers on reboot with proxmox was a PITA getting them back. Since I have 20tb drives, I don’t do any raid or anything like that, just straight drive presentation.
I am not sure some stamped tin and a few circuit boards are worth $1000.
IMHO this is just a $150 Rosewill RSV-R4200U with backplanes, so maybe $300 max.
I would MAYBE think about this if it came fully function certified system for $1000 that I could just drop drives into, but even then that is out of the typical homelab price point and entering the SHO market.