Bloom’s EPUB output is based on the EPUB 3.0 standard. That standard supports video as well as audio. (Bloom, of course, already handles audio.) There are thorny issues, I gather, in doing this, but in theory, a Bloom EPUB could include video clips. The actual video can be embedded in the EPUB package, or it could be included by URL.
A big reason to do this would be for creating accessible EPUBs. A book with audio can be accessible to a blind person or someone who cannot read. A book with video can be accessible to someone who is deaf or has a hearing impairment, if the signed version of the text is displayed.
Bloom is designed to help create literature for those who lack it. Bloom’s impact could be broadened if its books could also be accessible to people with disabilities. And books for those who read can also be enhanced. For example, a “how to” book could include a video clip of the task in question being demonstrated. I’m sure people would come up with other creative ways to enhance the value of Bloom books by including video.