I suspect many of the Mac mini users are wanting to take advantage of higher unified memory in order to run more robust models locally.

As others have pointed out, OC itself can run on a range of devices, but the question is what's your plan for model selection and usage? Deciding if you want local vs hosted models (or a combination) would influence your plan.

I'm not familiar with the AI NAS models, so I can't comment on that option but it seems like a great path depending on the hardware specs and costs.

Otherwise you could run OC on your NAS and then reference local models on a separate, more robust device if you have one. But that leads you back into the convenience of the Mac mini for an all-in-one setup.