Both CSM and CSPO certification carry their own value and their own weight, one job can demand you to be CSM versus another one can ask you to be a CSPO. Yes, there is a difference. This is the big question. And, who to better tell us about the courses than the Scrum Alliance itself:

CSM Course and Certification: “Our CSM trainers will teach you what you need to know to fill the role of Scrum Master (or Scrum team member). This course focuses on the basics of the Scrum framework, including team roles, activities, and artifacts, so that you can be an effective member of a Scrum team.”

CSPO Course and Certification: “The CSPO course gives you enough information to understand how Scrum works, but focuses mainly on functioning as the product owner, or customer, for a Scrum team. You will learn about activities such as managing stakeholders, ROI, backlog grooming, creating effective stories, acceptance criteria for stories, defining done, and so on.”