WF-BATCH is a system user. It is used to execute and manage all the background jobs in workflow. It has given SAP_ALL authorization so that the user have the proper authorizations to do any modification in the database or to open any transaction from workflow. Thus by assigning SAP_ALL authorization you are making sure that the Workflow administrator is able to performe his assigned work without any errors.
WF-BATCH is a System User and not a Dialog user so you cannot logon with this user. You will have to give the following areas complete authority to WF-BATCH.
a) To access all workflow areas.
- S_WF_ADMIN,
- S_WF_ALL
b) Complete RFC admin profile like access to SM59 etc.
c) Create, change and display access for the transactions that you are using in your workflows.
One has to do extensive testing to come out with a correct profile WF-BATCH. It will vary from company to company and system to system.