Managing code snippets is extremely important when it comes to doing development. Because it is extremely difficult to remember all the things a programming language can do, while trying to solve a difficult problem. Even more so if you aren’t familiar with that language.
Having ready-baked software that you have tested makes development significantly easier. Forgot a specific syntax? Forgot how to write an algorithm in a specific language? Forgot what a function does and the language’s official documentation / examples are too hard to relate too? Can’t recall which function should be used for converting strings to array, or different data types? Can’t trust someone elses code until you’ve tested and verified it yourself on your machine?