Rendering on the MacMini you're going to run out of RAM very, very quickly.
Not necessarily, I can’t speak for M1 machine since I don’t have one, but even on standard Intel system MacOS is very efficient regarding memory management and remarkably stable. I own and use both Mac and Windows PC(both Intel and AMD) and while both OS should support compressed memory, that really work way better on Mac.
Years ago I was able to render a very large scene within 16GB on an old MacBookPro, the same scene required more than twice as much physical RAM on other systems equipped with 64GB, the MBP was still able to render without mayor slowdown/instability.
The new hardware/OS should work even better in that regard, so why I do agree that 16GB maybe few for some (including me) it may be plenty for many, after all GPU folks are still working with less than that on average;)
Always remember that this machines are just entry level systems, and probably their target audience will find 16GB sufficient for their needs, of course for more heavy tasks is better to wait for proper hardware with more physical RAM.