How to grab attention with product walk-through videos?

I haven't discovered the answer yet. That's why I want to hear from YOU.

While applying for an accelerator recently, we received feedback from a coach who said "if you spend time making your video production ready with effects and editing, that counts against you because it could have been time you spent building your product."

This struck us as strange.

Be it a figma file, a physical wireframe, or something else ... how do you grab and maintain investor/customer attention in your product walk through videos? Is narration a must, or does a silent video work just as well? Do you add in transitions and effects? Does text overlay help in communicating the message?

In the linked video to our sample on-boarding flow (in comments), we went for the bare bones approach following our coach's advice. Does this communicate what our product is capable of, or does it leave out too much? What have other indiehackers done when trying to demo an in-progress product?