It can be used to create an infinity bow, which is by definition a bow with no maximum fire rate. This does not confer any benefit because the firing speed of bows is capped at 20 shots per second in Minecraft anyways.
Infinity 1 was designed to give players a way around the game limitations, and instead focus on fancier looking items, textures and gameplay challenges together without having to play towards allowing game-breaking features. By being able to cap shooting at 20 times per second it means that all those extra nails are for nothing because you won’t be able to make arrows fast enough anyway. It seems that misusing this option just comes down to aesthetics rather than actually making any noticeable difference in gameplay or challenge!