Is this a big deal? I clicked on this skeptically, but...it actually seems like kind of a big deal? It is at least technically impressive, since it seems like they're eliminated a ton of datacenter pain points with the mechanical design.
Also a former employer who was a bit below the hyperscaler level also had what they called "roll-in racks", though I believe they were just taking standard servers and networking gear and integrating them somewhere (presumably with cheap labor) and then bringing them into the DC as needed.
So I don't think it's a particularly new concept, but I agree it looks like it has some potential as a product.
Also, I remember for example HP BladeCenter BL20p systems. There you would have up to 8 or 16 servers per 6 rack units IIRC. So about 56 to 112 servers in 42U.