Just to clarify your point:
I’m not sure but I don’t think you can use root motion on a blend space, so far I think it’s just used on animation montages
Root motions are not limited to montages only. This is common in the AAA game development industry. That is why I said, it is not easy to set up. Plus root motion is designed to follows the movement curve of the animation, which has variable movement speeds and translation.
You can use it in the blend space as well. Keep in mind that root motion setup is not the same as in-place animation.