Words can flow well, but you need a strategy to determine their purpose and your audience.
Elaine L. Orr has published more than thirty books, some on her own and some with a publisher. She spent a great deal of time learning the ins and outs of the business, but she realized that she only really needed to know ten percent of what she'd learned. Since then, she has helped others take their book ideas to fruition.
Sometimes she presents material at a conference or as a lecturer. That's time consuming, so she wrote blog posts to direct aspiring authors to. That meant advice was scattered among posts, and even an index was insufficient for a comprehensive approach.
Then she thought, why not write a book? Writing When Time is Scarce and Getting the Work Published brings together thought processes and practical steps for authors. Books are great, but not necessarily flexible.
Online classes are very flexible. A student can read the materials anytime and the teacher can easily update the curriculum.
Does that mean writing a book is easy? Get prepared to think through your ideas and your publishing options, and put those ideas to work.