This video caught my attention because clusters are a favorite hobby.
I’ve written and deleted this post several times because I’ve been trying to develop a convincing POV. In the end I think you’ll have to experience it for yourself. But take my opinion for what it’s worth:
Having a fleet of micro PCs generating heat for it’s own sake has it’s own cost and no advantage. Especially with free ESXi available.
One reason I deployed Chromebooks in my house is because the cost of protecting all that data and having to maintain all those machines was higher than I wanted. Every time I open my Macbook I have to do an update.