Sure:
Whatever code we write as developers is only very tip of a the iceberg of software that comprises any substantial application. Controlling what goes into that iceberg, and how it's assembled is an essential part of the engineering of software. The details and quality of your build system determine the composition and construction of that iceberg, not to mentioned the reliability and velocity of your development process.
Even 'basic' local build systems like CMake, maven/gradle/ivy, sbt, lein, cargo, go, ... bridge dependency management and task execution. They decide what goes into the software artifact you ultimately distribute (or deploy), and how that's assembled.
At the scale of buck, bazel, ... tools of that shape are necessary to make forward progress in that's composed of internal dependencies that are managed by different teams, written in different languages, targeting a variety of environments, that are so numerous they require distribution to complete in reasonable timeframes, and require absolute.
I'm not VS/C# user, but MSBuild is definitely a build system, and both in and the developer definitely have care about these complexities, even if they come under the heading of "IDE" instead of "Build System".
Also:
As the joke in my first comment implied, if you can't identify the build system, you're probably the build system