As you said, all the workbooks were placed in Default Project in the Server, the existed other projects being not utilized. we do not have any pros about it. May be the other projects created for future purpose. Please check with is any reason behind why existed other projects being not utilized. OR check with your server Admin, may be server admin will be moving workbooks to other projects which you dont have access.
1 of 1 people found this helpful
The default project is helpful for setting the default permissions for new projects as they are created. Whatever the permissions are on default are automatically copied over to new projects as they are created.
As a best practice I recommend never intentionally putting workbooks in the default project. I like to use it as a catch-all for mistakes when content owners make a mistake in the publishing process. Since each piece of content has an owner you can contact them and ask each owner to republish the content to the proper project.
For more information on Tableau Server projects check out the following resources: