Fantastic idea David. I was not thinking about this product as a tool for video generators. Are you imagining a product in which you would add some links and then get a video in return?
You say that you would invest in tools that simplify your process of generating video. What’s the one part of this process you would love to have generated by a product/service? Imagine that you had an assistant but this person can do only one thing, what would it be?
When I made the prototype I had a “video digest” in mind, like a newsletter but instead of getting an email you would get one video that narrates the latest posts in the topics you showed interest on. So the type of user was more like a regular newsletter subscribe

Now regarding your question of compute time vs subscription cost, could you please reframe it or give me some more information? It’s not clear for me what is it that you want to know.
Thank you very much David for sharing your idea
