Excluding using as a Plex server or running a business, do you find having a NAS useful in your household? I'm struggling to find the practical benefits over cloud storage (e.g Google photos,drive etc.) outside cost and privacy.
I think you've nailed it there in your question.
If you don't want or need to host stuff locally, like Plex, Unify, Home Assistant, etc. and you have no data you want to store locally for fast retrieval, then it really becomes a bit of a dead device.
Even if you torrent, you can effectively use torrent sites as your NAS.
And I'm even of the opinion that entry level on NAS doesn't make much sense to me.
For example a NAS that doesn't actually have redundant storage and doesn't have enough RAM to host a bunch of stuff seems totally pointless to me.
The whole replication to multiple devices thing, to me, is also a bit of a "err, should you be doing that?", kind of discussion.
I'd use something like S3 Glacier Deep Archive option instead, as the nuclear option (ie. everything else has died).
If you are storing you "ISOs" on something like that you need to get your head examined.
And if you run a business, you'd have to get your head examined for not storing with something like that, for backup, if it is business critical.
An argument could be made, as a shareholder of a company that you are not doing due diligence if you are only using your own NAS devices.
Because in the end it is about data retrieval. If you NAS device is the same hardware in 3 locations you are still very vulnerable to a year 2000 type bug or various other scenarios.
You really should be using cold storage that uses a completely different mechanism for that if it is a risk to a business