This '
deep color' mode is just 30/36/48-bit SDR rendering, within the regular sRGB color space using standard gamma 2.2 curve. It does not provide wide color gamut for purer colors, or HDR EOTF curves for inscreased highlight brightness - so the effect will be quite subtle, if at all noticeable.
The effect of HDR10 displays on current generation games would be limited to better highlights and contrast, as HDR10 support is currently achieved through post-processing steps. Increased color gamut would require both rendering and art authoring in a wide gamut color space, such as scRGB.
Nvidia has a
detailed white paper on the use of wide color gamut in game production:
https://developer.nvidia.com/high-dynamic-range-display-development