Case study videos are a great way to showcase work that you have done for clients/industry verticals, how your product or service works and how it has improved processes, business, ROI, efficiency, work life etc. Case studies help potential customers understand the value your company brings to the table. They also provide credibility, especially if you have worked with well-known brands that people recognize. It's important that these videos are well shot and engaging. It’s also best to keep them as short as possible since attention spans are fast shrinking as more and more content populates the world wide web. Having said that, if your audience is a niche one and is looking for the type of solution you provide, they may give you more time to explain what you do and how it’s useful. You can gauge this depending on where they are likely to be in the sales funnel.