First off I'll say that any other responses you get will likely be biased response (much like my own) towards the "yes, use DNN" arena. I'll site an example or two and then leave it up to you for the real decision.
I say yes, use DNN, because, if nothing else, there are plenty of tools to make it easy to manage the content from an admin perspective rather than having a developer have to do everything any time you wanted to change content. My step-dad, for example, has a small website for his music. He goes and plays gigs for old-folks homes and wants a website for them to come look at. Initially I helped him create the structure (several years ago) in straight HTML. Over time the site got messy and just plain messed up. By that time I was well-entrenched in DNN and thought that it would serve him well.
Long story short, my step-dad doesn't need (nor want) people to register for his site as it is purely informational and public. However, he wants to be able to go change content, upload photos, etc, on a whim without screwing up the structure too much. I found DNN to be a perfect solution because I could design a skin that would work for him, and then let him create/change content to his hearts content after a couple lessons. His site works well for him: http://www.bobwallacemusic.com
Another example is my mom. She breeds show-quality dogs as a side business and, much like my step-dad, is not all that computer savvy but wanted a website to showcase her dogs, etc. She is a little more forward about trying to manage her own site and, as such, it has become a little messy, but overall the fact that she can worry about managing her own content and leaving any upgrades or maintenance to me. Her site is http://www.besemehavanese.com
So yes, I say go for it unless there are any really good reasons NOT to do it.