There is that doesn't require payment. Any tool claiming to do this is either a scam, illegal, or both. Respect copyright and either purchase the license or use truly free alternatives.
The watermark ensures that:
She searches Google: “iStock video downloader without watermark.” Dozens of shady sites pop up. Some promise “free premium downloads.” Others require installing a suspicious browser extension. She knows the truth: istockphoto video downloader without watermark
You have a professional final video, you paid legally, and you never wasted time searching for a fake "downloader." There is that doesn't require payment
: Offers HD stock videos for both commercial and personal use with no attribution required. you paid legally