10-bit means each colour component of a pixel can take 1024 distinct values (instead of 256 in 8-bit), giving over a billion combinations per pixel. Visually, the difference shows up in two places: smooth gradients (sunset skies, foggy mornings, dark night scenes) become genuinely smooth instead of stair-stepped, and HDR brightness can be represented without ugly banding.
For HDR delivery — HDR10, HDR10+, Dolby Vision — 10-bit isn't optional, it's required. The HDR brightness range is so much wider than SDR that 8-bit would produce obvious banding on any darkish wall. So if your product is going to claim "HDR support", 10-bit is part of the price of admission.
A useful surprise from the encoding side: in HEVC, AV1 and VVC, encoding at 10-bit often produces a slightly smaller file at the same quality than the 8-bit equivalent — typically 5–15 % saved on streaming bitrates. The catch is decoding cost: 10-bit playback is heavier on older or budget hardware. Practical answer in 2026: virtually every device sold in the last five years decodes 10-bit HEVC and AV1 in hardware without breaking a sweat, so the "8-bit is safer" argument is mostly a legacy concern now.
