Logging always felt like something that (1) almost every project needs, and (2) there are too many 3rd party packages, with no "de facto" choice.
This is particularly painful when working with 3rd party library code. There's a high chance that the consumer of library code uses a different logging package to the library author.
Having structured logging in the stdlib is fantastic, because now there is a "go way" to this that libraries can use.