With educators and researchers newly embracing computing as a core component of curricula across all STEM disciplines, there is an urgent need to understand the specific challenges and opportunities computing can pose when it comes to supporting student learning. In this talk, I address this emergent problem by demonstrating the findings of a study conducted for that purpose in an introductory undergraduate interdisciplinary computing course. My team conducted interviews with students to gain insight into how their experiences aligned with the development of self-efficacy, a psychosocial construct known to be tied to persistence, aspirations, interests, identity, and academic performance. We then connected these experiences to student-articulated aspects of the course design to show how students can be supported when using computing as a tool for disciplinary learning, including physics. We found significance in experiences of struggle and success, as well as sweeping implications for the importance of personally relevant course material, curricular emphasis on building resources, and investments in supportive group dynamics. These findings bring fresh questions and challenges to physics classrooms and curricula where computing is used, which I will also discuss.