That's why we build Fluxcut (fluxcut.dev) with a product demo video engine as the filming studio putting together scripting, timeline arrangement, footage section, voiceover, background music and thumbnail so that creators have an all-in-one solution for the product demo.
While we design the engine of product demo video, we do not exclude the status quo agent such as Claude Code which are very powerful. I personally often ask Claude to apply the Fluxcut plugin (https://github.com/Flux-AI-Agent/fluxcut-plugin) to come out an initial version of the product demo quickly. Then I can tweak those parts that requires further improvement. This practice makes creating product demo videos so easy and so much fun since the process is not a blackbox for us and we can involve with any part we want!
It's also very easy to update some part of the video, whether it's the script, footage, VO or BGM, since every part is just at hand and ready to be edited. The cool thing is editing some part does not necessarily affect others and things often follow through very well.