You can embed Audio and Video easily with their respective element tags. This will cut down on some of the code bloat.
In terms of SEO, these new Element tags will allow the indexing of your site easily especially if you have Flash on your site, so get ready to see more results show up in the SERPS. These Element tags also work like Meta-tags, they let you describe what kind of information is on the page.
Devices that use updated browser's will not need to worry about Flash, as we all know by now Adobe is discontinuing support for Flash on mobile devices and turning their focus for the support of HTML 5 development. I included some more info here on the HTML 5 Page.