The package we’ve created so far has a relatively basic script interface and no extensibility. The majority of applications do not need a way to be extended; it is often easier to package all optional code together rather than go to the trouble of maintaining plugins that are distributed apart from the main codebase. However, it can be very appealing to use a plugin architecture to manage (for example) optional features of an application.
If your direct users are other programmers, then it might be a good idea to provide a plugin architecture to make their jobs easier. This ...