I'm curious why you think hg had a prominent role in this. I mean, it did pop up at almost exactly the same time for exactly the same reasons (BK, kernel drama) but I don't see evidence of Matt's benchmarks or development affecting the Git design decisions at all.

Here's one of the first threads where Matt (Olivia) introduces the project and benchmarks, but it seems like the list finds it unremarkable enough comparatively to not dig into it much:

https://lore.kernel.org/git/Pine.LNX.4.58.0504251859550.1890...

I agree that the UI is generally better and some decisions where arguably better (changeset evolution, which came much later, is pretty amazing) but I have a hard time agreeing that hg influenced Git in some fundamental way.