Wireframes are like blueprints, its a vision. And if vision or blueprint is clear final result has to be clear. If you are a designer then wireframe would be helpful to share a layout with your clients.

If you are working on big plugin then you must draw rough wireframes of different setting screens involved in the plugin developent.

Different wireframing tools:

1. Google Docs' Drawing tool - What you need is just a free google account.
2. Diagramly (now draw.io) This also allows you to share the wireframe with your google drive
3. Moqups - This is more intutive. The premium account will allow you to have collaborative sharing.