If you are reading this book, you might have seen a lot of basic examples of software delivery chains and branching models. It is very likely that you have been trying to use different strategies and found that none of them completely supports your scenario, which is perfectly fine as long as the tool can support your specific workflow.
Git supports almost any workflow. I have often encountered a situation that requires a merge commit while merging a feature, even though it can be done with a fast-forward merge. Those who requested it often use it to indicate that you have actually merged in a feature and want to store the information in the repository.