I'm a programmer, at least occasionally, and Soulver is a pleasant, user-friendly tool to me. When I open Soulver, it's because I want to do some unstructured multistep math work and it's faster and easier to do it in Soulver than a spreadsheet program. Jupyter Notebook could undoubtedly do similar work, but it doesn't read to me like it would be the best tool for the job.