From a user perspective I often implement a feature and then just throw it away no worries because I can reimplement it in an hour again based on my findings. No sunken cost. Also I can implement very small details that otherwise I'd have to backlog. This leads to a higher quality product for the user.

From a code standpoint I frequently do large refactors that also would never have been worth it by hand. I have a level of test coverage that would be infeasible for a one man show.