The decision to publish both a print edition and an ebook edition is a content management strategy. Readers have different buying preferences. Some readers like printed books and others like ebooks, and some even want both. Some people want to read ebooks on tablets, some want to use phones, some use particular brands of e-reading devices. As a publisher of content, you must decide if you want to reach some or all these categories of readers. That decision is your strategy and different goals sometimes require different approaches for how the content is prepared.
For example, you may decide to offer a black and white print edition of a book to save money on print, but then offer a color ebook edition. In the planning stage the source file needs to be prepared in color and then converted to black and white.
Another example would be deciding whether to convert a textbook to ebooks that only work on tablets or reworking contents so that the layout and graphics would remain readable on phones.
More advanced strategies include how you want to market the book. For example, some publishers will release chapters of an ebook, one at a time, for free, to generate interest in an author or publication. They may then sell the ebook in a complete edition.
Another strategy is to give away some content while selling the premium or core content separately. A “book” is just one way to package and distribute content. The same content can be reworked for different types of readers, just as it can be formatted for different types of reading devices. A “how-to” book can also become a student manual with a separate teacher’s manual, or even a business fiction novel. People want information, but often like to get it in different ways. The user experience is important. Some people like to be immersed in a large book, other prefer content in a series of shorter volumes. Readers often prefer long novels and short “how-to” books. The best strategy for how you manage and publish your content often depends on your audience’s preferences or how many audiences you want to reach with your ideas.