When the gov.uk team offer a rundown like this, you have to read it because that team are some of the best in the business of great user experience. We’re so lucky in the UK because anything government related is so easy to use. They are, of course very into progressive enhancement to achieve those excellent results.
For users to experience a quality service it must be built in a robust way.
Progressive enhancement is a way of building websites and applications based on the idea that you should make your page work with HTML first.
Says it all really!
If for some reason you’re asking “why should I bother with progressive enhancement”, make sure you hang on every word of this article.