The reason to use specialized code is because your needs match them. Not everyone wants to bother linking to a general purpose library and adding a dependency when you can reuse some specific code and be done with it. Also, language standards cover libraries extensively and this is hardly a new trend and once it is standardized, it can no longer be considered third party. This has already happened quite a bit with C++11 which standardized many commonly used portions of the Boost library. Nevertheless, I mentioned the standardization aspect not to debate about it but to use it as an example to point out competing projects.
