HDR, or high dynamic range, is a technology that enhances the contrast and color of an image to make it look more vivid and lifelike. Many streaming services, including YouTube TV, support HDR content, so having a TV with HDR can enhance your streaming experience. However, it's worth noting that not all HDR implementations are created equal. There are several competing HDR formats, including HDR10, Dolby Vision, and HLG, and not all TVs support all formats. HDR content is also relatively limited compared to standard dynamic range content, so that it may be challenging for some. Ultimately, whether HDR is important for your streaming setup depends on your preferences and how much you prioritize image quality.