We write comments for everything in our code because those comments are used to generate documentation!
See https://blog.golang.org/godoc-documenting-go-code.
"Self-Documenting code via commenting is extremely nice to have 
Sometimes it’s easy to skip writing those comments, but I always go back and write them if anyone else is going to look at the code, or just for my own future reference. Coming back to my own code is much easier when it’s commented. What seems obvious in the moment is not obvious 11 months after when you have to fix some bug you have missed or are re-writing something you have not touched in a long time