i think video marketing does not exist.Only advertising thru videos
Marketing (
https://www.smallbusiness.wa.gov.au/business-topics/marketing/marketing-strategies/) is different thing than advertising. Advertising is the result/tool of marketing in my oppinion.
I think that videos are important part of promoting/advertising. To develop the video right, the marketing department must be involved as the videos can greatly influence potential or existing customer in the way the video author wishes.