DietPi for PC works fantastic and I’d argue is probably easier than setting up ROCK given that you don’t have to mess with Codecs as it comes with the codes already in the OS.
Additionally, it allows you to run the Roon Extension manager, Tailscale, and other things as you may want on the same box. And, it lets you monitor temperatures.
Absolutely agree. I started writing a reply to this extent earlier but thought I had said this too many times already, so I deleted it.
More than happy to add my voice in support of your statement though as it has been working perfectly for me since February.
A great experience so far 
It should, it is the same RoonServer software. ROCK isn’t really about RoonServer but the OS RoonServer is installed on. RoonOS is trimmed down, but, a basic command line Linux install is already pretty lean.
DietPi has the advantage over a standard Linux distro because of the installation script which creates a menu to select and install software.
I also started writing in praise of DietPi - and for much the same reasons as @Rugby and @Michael_Harris have described above.
The only caviat to the use of DietPi is that it is somewhat more difficult to switch between production and early access versions of Roon Server.
See:
@Rugby , there must be someone that can ask Danny what the status of RoonOS 2.0 is? Danny asked us for RoonOS 2.0 feedback, which numerous subscribers gave, in detail. It shouldn’t be awkward for Danny to give us an update on the progress. Cheers.
my ROCK is running on a Topton Fanless AMD Mini PC. 16GB DDR4 512GB NVMe, Ryzen 7, 5800U. So, you do not need a NUC.
If you need support from Roon, than you do.
Torben
Life is full of ifs… So go with NUC.