Quite simply, because the Kindle is only available at the Kindle store and only for devices using the Kindle app. A Multi-format ebook, on the other hand, can be read on most e-readers, using all sorts of different apps or built-in programs. It therefore can be sold at B&N, iTunes, Kobo, and via any number of online vendors all around the world. MFE files can be converted into audiobooks, RAL ePubs (Read-Aloud ePubs), and Apple Apps, which are perfect for children’s books, with a lot of interactive features! There is a huge demand for digital content globally and having your book available in multi-format also means it can be included in catalogues for foreign rights sales (our sister company ePubco’s catalogue, for example, goes to every book fair and is shown to every potential foreign-rights partner).
Having a digital version of your book is a way to broaden your reach, so don’t limit it by just doing a Kindle!