Yes, while the page here does not directly mention the prompts, the linked paper does, and the linked code repo shows that prompts are used as well.

100%. I don't think I've ever even come across an I2V model that didn't require at least a positive prompt. Some people get around it by integrating a vision LLM into their ComfyUI workflows however.

Ah yeah you're right - they seem to just really like giving dancing prompts. I guess they work well due to the training set.