It's not bloat in the source code - if you don't care which pieces you depend on you declare a dependency on math, if you do care you list the specific pieces.
It shouldn't be (impactful) bloat or overhead in the build system or dependency management. That stuff should just handle it.
Most of the time you don't care and can just declare the dependency on math and let the closure compiler handle it. But sometimes it might be really important that a project only used cos and not sinh, in which case you want to enforce that.
