I really love adding free custom text / annotations to my dashboards we are using and scheduling nowadays, because that way I can "automatically" answer and explain what some difficult stats might mean and that way I get less emails with questions "what does that stat X mean?" etc. Again not the most important feature and this comes more needed in the future when we can (hopefully) schedule these Analysis Workspace reports too.
I believe we are planning to offer annotations in Analysis Workspace at some point, although possibly after we release Analysis Workspace to production. We recognize that the ability to add context to your projects is key to democratizing analysis!