The main problem I see is that if this is any cheaper than it's hardware, people will buy 100s of them and stack them in server racks for CI runners or whatever. Generating only losses for Valve and making the hardware unavailable to gamers.

It needs to either be at market rate or locked down to only be useful for gaming.

Iiuc, unlike Sony’s PS3 (which were bought and used like this), Steam is the unique distributor so it would be easy for them to not allow (or make really difficult to) buying thousands of machines.

(Or they could sell it everywhere for higher price but the Machine would come with a non transferable Steam gift card.)

I think the limitation on server gear these days is electricity price vs compute, with the hardware price being an up front investment but not dominating the lifetime cost. At least at this end of the price range - it's a consumer GPU, not an A100 or anything.

you don't remember playstation clusters?

https://en.wikipedia.org/wiki/PlayStation_3_cluster

that said, practically buying hundreds of them should prove to be quite difficult.