git feature branch: rebase -i or merge --no-ff?

git feature branch: rebase -i or merge --no-ff?

Many git workflows advocate doing a git merge --no-ff to bring a feature
branch into the mainline. I personally prefer to git rebase -i my feature
branch into one clean commit, and then do a simple git merge of that.
Is there any downside to using rebase -i this way instead of merge --no-ff
for feature branches?