The name of the article is "What is a build system and what is CI?" but my main take away is really the realisation that most/many companies aren't really doing CI, they're doing instead CBOI: Continuous Build, Occasional Integration.
Also, wow, there are very efficient build systems that all devs should really know about, like Bazel.
He is missing integration tests in CI pipelines, and his only idea to this problem is to sell Bazel. Whilst he should propose to fix the problem by doing proper integration tests.