Deployment can be a time-wasting issue for a web application, and arranging your system “to be easily compatible with Plack” is a way to save a lot of that time, if it works for you and your application.

Changing the method of deployment is, traditionally, an even more tricky thing to do, coming as it usually does when the app has become a “legacy system.”   Once again, this might make things easier.   The app code that you write becomes more platform-agnostic, with the actual set of necessary changes being concentrated into a much smaller place.