We recently did an article on why you should get an editor, this article is for why you should publish your work after you are done editing it. Publishing your work makes it available to a wide audience that can reuse and share your work.
Publishing your book makes you and your work more recognizable. It helps you to create and sustain a reputation. Your published book is likely to get you to more places than with just words of mouth. For example, if you are the first in your field to discover something or write about something, if it is unpublished, the writer might go unknown and not given the necessary recognition.
When you publish, you are making yourself more credible in your field and this can help move your career forward and you can even use it build your portfolio. You are considered an authority on what you have published on.
Imagine when you are done writing and editing a book, you just leave it on the shelf. It is very likely to go unused but publishing makes your work discoverable. Most online published works are made available by indexing them into online databases.
The work is more likely to be reused
Your published book is like a document. The information that is contained in it, if it is beneficial to someone, it is likely to get used than when it is not published. Other people in your field can also learn from it and even build up on it. Most works have probably been forgotten or lost since they were not published.
Your work gets more awareness
Another reason why you should publish is because it makes your work more citable and a work that can be cited is more known than one that is not
There is more access to your work
Publishing your work is a way of sharing information on a part of your field that you are very knowledgeable about. You give people more access to reuse (of course, with proper references).
Usage of peer-review
When you want to publish your book, your work gets peer-reviewed. This makes sure that the final product that comes out is of the highest quality. Papers are evaluated by experts in that field that make sure the work is up to standard.
Service of experts
Publishers make sure the work has standard contents that can be discovered and reused. Publications is handled in a standard and professional way.
Usage of technology
With the advancement your technology, publishing online means that your work can be seen, accessed and reused forever. Unless the journal you publish decides to close down their business, anybody can access your work globally forever.