But it apparently does work:
However, since it is not on the supported hardware list, it may work for some people but not for others.
For example, on some devices, USB audio does not work - but it a user is not using USB audio, then maybe that does not matter to them and they report ‘no problems’ just because they have not encountered the problems whilst another person who uses USB audio will report 'not compatible because they have encountered the issues.
Note: I’m not saying that RoonOS (as installed by ROCK) on the NUC 14 Pro does not support USB audio - I just used that as an example.
However, you should probably not rely on any one report of success unless the reporter details his setup and it can be seen that they are exercising all aspects of RoonOS (or, at the very least, all the aspects that you are interested in).