Just wanted to pop in to say that I decided to try using Cypress E2E tests for TDD as my only testing for my current side project, and I'm enjoying it! I know I will want to use this project, so it's worth testing it. But due to the experimental nature of it, a lot of internals might change, so I'm hesitant to write component tests of any kind. I just did a major architectural refactor that my Cypress suite supported. And I might even need to switch frontend frameworks someday; Cypress E2E tests will cover that change too! (I do think I'll add true unit tests for pure JS functions that I know will persist regardless of the framework.)