Background video can be very effective on a website, if used sparingly by a good designer. If you’re making an attention-grabbing landing page (and for a major promotional campaign, you should be), then it’s something to think about.
By definition, background video is just that. It won’t have start and stop controls, and probably no audio; it’ll just run in the background, creating a feel for the offering. Service agencies often use it well, but product presentations can be enhanced too. Here’s a gorgeous example, taken from a long list of sites using video in this way.
Don’t forget, background video is there to position the product or service at a glance. So it should be relevant! Simple text can run on top of it, but nothing complex – that’s for the next step. If you’re thinking: “Why not take people directly to the next step?”, you probably have a product or service where immediate explanation is everything, and background video may not be the right thing.
On this site, the mobile version shows a still shot, while the desktop version shows the video, cleverly including lots of text to read while still leaving room for the video. Note how the video is short and on a loop, so it’s not a big download – which can be critical. People won’t wait around for things to load.
While I’m sure most readers won’t be rushing to convert their home page to look as good as the first example above, it might be something to consider for future projects.