It makes is substantially easier to work with known design docs, and RasPi want people to use their hardware in embedded applications.
It's not like you can replicate their hardware with just the schematic. Its awesome to see other filling the gap, but its a gap that has no need to exist.
Out of lack of understanding: what does this new knowledge allow? Will it allow open-source developers to write better drivers? Or does it allow the making clones? Or nothing in particular?
You could use this to make clones - but only if you could source at least the BCM2712 SoC, preferably RP1 too. I can't imagine that happening in practice.
This is the old analog CT method: sanding