Video is great for:
- getting visitors hooked and converting to users
- in-depth tutorials on how to do something where the viewer is motivated to find out
Both of these don’t apply to onboarding (generally) and I think that’s why they haven’t worked well in my experience.
What has tended to work for me have been emails, which function more like drip emails. That is, each email has basically one ask - for the reader to complete one task. I see onboarding as a series of small tasks to get the user to a stage where they are wowed by your product, and have found light email prompts to be effective.