I don't think this feature is very well-known, in fact I've seen it mentioned before, thought "how useful! I will absorb this into my brain now" – and promptly

I don't think this feature is very well-known, in fact I've seen it mentioned before, thought "how useful! I will absorb this into my brain now" – and promptly forgot about it. I think there is a critical mass of advanced git features required to be really fluent in git, and there is a sizeable fraction of everyday git users who simply haven't made it all the way there yet. Some teams have at least one person who has enough git features under their belt... To recognize when merge conflicts are being haphazardly made unnecessarily, to be really particular about the shape of the git commit history and be aware of what merges can make those conflicts, to occasionally show the rest of the team some of these tricks or bail someone out when things go haywire, but at least in my experience spreading all of this knowledge to the rest of the team is a long slow process.