I believe testimonials, either written or recorded, are a strong marketing trick. One thing I want to see in testimonials is that the people are REAL people. This is why on our website, we've also added people's LI profiles :)
Video testimonials are important for sure - there's a growing scepticism of vendors who just have customer 'logos' on a website, or anonymous case studies.
The thing that's important is that for the end user it's really clear the view is from a real person, from a real company. So having a video with someone talking about your product glowingly, will help you stand out a bit from the crowd
Hope this helps :)
Video testimonials are the most impactful social proof that can help you grow a brand so I would say it's a must if you want to convert more leads.
If you want to collect video testimonials from customers maybe you should try Snackeet, it's a no-code tool to create web stories that you can share everywhere to collect feedback and testimonial from customers :)