From the "Best Practices for Web Developers" section:

It’s worth pointing out that the new auto-play policies apply both to video used as a tool for making something visual happen (like background video or video-as-animated-gif) and also to video that serves as consumable content. We recommend web developers test their site with these new behaviors, ensuring any custom media controls behave correctly when auto-play is disabled, either automatically by Safari or by users.

I.e. you now need to verify that your site still looks good and works well when background video auto-play has been denied.