But, Valve literally pick up and implement what Overwatch did and input buffering is not new as well since Rocket League used it for a long time, also partially thanks to Overwatch dev if you watch Psyonix's GDC talk. So yeah, many game dev does innovate through out, and don't credit everything when Valve implement what other did and maybe make other improvement along the way. That's how everyone improve, by learning from each other.

Agreed, it's a good system and is more accurate than 128tick, even though it's not perfect. E.g. the client still only shows the muzzle flash on the next tick, so up to 16ms after the shot was actually fired [1]. This is probably one of the reasons some people can tell the difference between 64 and 128tick, as the game might feel more accurate, even though the hit registration isn't in any meaningful way.

[1] https://www.youtube.com/watch?v=4jfo6sWhLFs