The Competition Pro is one the best joysticks for the Amiga and Atari. I used to have mine connect to my MSX. It's solid stick but only useful for games that requires one fire button.
But why a the Competition Pro to Turbo Grafx? Possibly modified a USB version, but this isn't ideal for the games on that system since it's mainly a one-button joystick. Maybe Nexzr can use it because you only need one fire button, but other tg16 games that require two buttons won't do.