You need to include Blog assets in the workflow because they need to be approved before you publish these assets.
The following topics provide information about creating workflows for Blog assets and publishing Blog assets:
You can use a workflow to manage the work on a blog asset. Before you can publish a blog asset, you must approve it for publishing. The workflow feature routes blog assets through the steps that you specify, from creation to approval.
For example, if you want an editor to review a blog asset before you approve it for publishing, the WebCenter Sites workflow feature can route that blog asset to the appropriate user at the appropriate time. See Creating and Managing Workflow Processes.