At times we want to create a UI framework with custom tags. In such a scenario, taglib is a very good feature of JSP. With taglib we can create tags that can provide custom features.
Taglib is also a nice way to communicate with UI designers who can use custom tags in the html without going into the details of how the code is implemented.
Another benefit of taglib is reusability of the code. This promotes writing code only once and using is multiple times.