Why don't they push build?

Question

git

In assemblies, for example Gulp, there is a src and build folder. In order for the project to work, it must be built into the build folder. Why they don’t push the build folder to github, but only src to build during deployment. Why, is it so convenient?

Answer 1

why? it is automatically assembled from sources.
Of course, you can push, but it will be a useless littering of the repository and its history.