Why is pull --rebase dangerous for a local branch?

Question

git

Good morning, what is dangerous git pull --rebasefor a local branch?

I use git-flow where for each feature there is a separate branch in which only 1 person works.
When updating master, you need to update this local branch as well, now I do it in *dev git pull origin & git merge master

But I would like to rebase so that my changes are on top of those that are already committed in master, but I read that you should not do this, but when you work on a branch 1 - why not?

Of course, then this branch will be sent to originand later merged withmaster