And at that scale (1k) it ain't even that hard, a single room could be enough to hazardly drop them on shelves with a big fan to draw out the heat

There are many people who do not have ready access to a million dollars to purchase said Mac minis, much less the operating capital to rack & operate them.

Very smart play to build a platform, get scale, and prove out the software. Then either add a small network fee (this could be on money movement on/off platform), add a higher tier of service for money, and/or just use the proof points to go get access to capital and become an operator in your own pool.