In my opinion, the most valued asset in SAP MM consultant has and must bring to their customers is the understanding of the end-to-end procurement and sourcing business processes in different industries.
How these skills will be applied on a daily basis naturally depends on the role being played in the project:
In a support role, the consultant is supposed to have an understanding of both standard forms of SAP implementation as well as good knowledge of the customers' processes template. In this scenario, the consultant would work on a break-fix basis (by addressing production issues with already implemented processes) or, eventually, small enhancements (when he/she will bring that market experience and local implementation experience together to propose and implement new functionalities)
In a project role, it’s expected the consultant has a great understanding of the customizing flexibility the tool provides, or in other words, the “can”and “can’t”s of the System. The consultant will have business interviews to determine the requirements, will propose solutions based on technical and business-related experience, will most likely defend more than one approach for addressing the requirement, will be able to provide the end-user with all impacts in both MM and subsequent SAP modules for josé solutions, will have the solution documented and approved and will work with implementing that functionality within a certain timeline. All these steps will require different levels of documents.
In summary, this is a role of dealing with business-oriented people and processes, of aggregating by bringing industry experience and discussing SAP’s approach, flexibility and constraints.