(Disclaimer: I work at Stripe and use Sorbet)

IMO the Sorbet additions do impact readability, but it dramatically improves understandability. In a codebase past a certain size/number of contributors, you're always going to have ambiguity about what sort of data you're working with. For example, in my part of the codebase we have models representing an entity that is identified by a number in external systems and represented as a whole data object in our code. If I have `foo.entity`, it's unclear just from the "real" code whether that'll return a data object or just the numerical identifier. Having the Sorbet annotations on that method (and available on hover in the IDE) make it a lot easier to navigate the codebase and resolve these ambiguities.