We have been using Git Flow in our team too. One advantage I se is that using git-flow specific hooks we add some metadata to every time a feature/ branch is finished. This metadata goes into an automatic Release notes file which is automatically added to the repo (as an amend of the flow's last commit).

Similarly, hotfixes have metadata which goes to their own hotfix.csv file.

A deploy script processes the hotfixes and feature files to create a Release notes.

We've got a very smooth release documentation process which is difficult for Dev's to hate and skip.