How much faster is it? See Timing. If the branch is currently checked out, then 10x is a reasonable estimate. If the branch is not checked out, then it’s even faster.

Is performance the only added feature? git move also offers several other quality-of-life improvements over git rebase. For example, it can move entire subtrees, not just branches. See the git move documentation for more information.

git move is part of the git-branchless suite. Cool stuff.