The primary incentive for the Day One Edition is a specific digital bonus included with the physical disc:
For those who appreciate the visual direction and lore of the series, the Day One Edition frequently included a digital artbook. SNK has a distinct art style—evolving from the pixel art of the 90s to the "dodgy" hand-drawn era of the 2000s, and now to the clean 3D models of today. the king of fighters xv day one edition
Here is exactly what you got inside the box (or digital download) that you would not get from the standard base game later in 2022 or 2023. The primary incentive for the Day One Edition