Possible application: https://thedailywtf.com/articles/What_Is_Truth_0x3f_
I want an LLM trained on dailywtf code
Off the top of my head. Compilers. You may know that a value has known 1s and 0s and unknowns. This would allow you to represent that for optimisation purposes.
I've seen this pattern repeated in a number of large production codebases using optional booleans.