Download the latest code and you'll find that support for image galleries is now available for self-hosted WordPress blogs . Previously this was only available to users of wordpress.com, now anyone who runs their own WordPress site can access this feature (it does require that the site is running WordPress v3.5 or higher).
The update also addresses 'the top 5 bugs' that the dev team are tracking. You can keep up to date with their progress through the weekly IRC based dev chats (and the summaries of those chats can be found online).
While some blog themes might not be set up to support galleries, if you have the code in the theme, they are a great way to show off photos taken while out and about with your smartphone, as Danilo Ercoli explains on the WordPress dev blog:
Galleries are a great way to share pictures with your friends and followers. An image gallery will display thumbnails for all images attached to a particular post or page. Readers can tap or click any image to launch the gallery full-screen, displaying huge versions of your images.
You can create a gallery straight from your device by attaching two or more pictures to a post or a page. You can even customize the appearance of a gallery by tapping the “gallery settings” button and choosing the best options for your site.