If you are doing this style exactly without git flow, you don't gain a whole lot. It is great if you are working with a team then it forces everyone to work the same way and is very clear what you do in each situation. One of my favorite features of git-flow is housekeeping, for features when you close them it merges to develop and destroys the branch, when you do a hotfix it merges to master and develop and destroys the branch. When you release it creates a tag with whatever version you specify, and you can work on that until you are happy with the state of release, then when you push tags you will have a nice snapshot of your last deploy.
tl;dr: good for teams, and housekeeping