I think that this is a useless thing that is impossible to mine coins and play, due to poor cooling and the impossibility of self-repair. For 600 dollars I will assemble an excellent computer from components. My computer will be bigger, but I have no problems with the installation space.
According to some discussions I found on Reddit and other social media, most miners agree that Mac is not the best hardware if you are looking for profit. Most of them consider mining on Mac just for fun and supporting the network, since their latest processor, while powerful for many tasks is not good enough for mining. I personally own a Macbook Air. It is a good device for office work, light gaming, content creation, etc, but I'd never consider mining on it. I don't think it changes with Mac Mini since most of the time they perform at the same range. The key differences are extra cooling and no battery.
Is this type of cooling still popular? I thought most companies and buyers prefer open-air fans or liquid cooling systems nowadays. AFAIK, blower-type cooling can be very loud, hence why it is not the most popular choice. I'm not sure about the performance but from skim-reading several articles there doesn't seem to be a big difference unless we compare it to liquid cooling. I guess the price is the key factor when a miner wants to buy GPUs since most of the time they are not that bothered by loud noise. CMIIW.