I guess they took inspiration from the competing Greenshot, where indeed it does remap that button to start the sniping tool right away. I've been enjoying this for many years already :D
They probably took inspiration from the decades of snipping tools on Linux doing exactly that on key press. PrintScreen was AFAIK already in use as a shortcut for the snipping tool in KDE and GNOME when i started using them in the mid '00s