Support for radio buttons.
In my UI dialog I have a drop down list that has all available options. It’s not as clear when looking at the UI that these options are available. To see all the options the user has to open the drown down list and scroll through.
Having a few radio buttons shows the user those options without them having to open the drop down list. Having radio buttons also help when reading documentation as you can see all the options in the dialog screen shots.