Two good reasons: it is an excellent way to practice using some more advanced C++ features and existing libraries may not be able to do what you want in the man

Two good reasons: it is an excellent way to practice using some more advanced C++ features and existing libraries may not be able to do what you want in the manner you want. Logging libraries are also a well-bounded project you can build and refine incrementally to a high degree of sophistication as a single dev. And of course, it eliminates a third-party code dependency in your other projects.