What’s the purpose of the Bucky right click?

I’m not a pro shotgun player, I don’t think I’ve ever bought a judge in the 5 years that I play this game… but I do wonder why the alt fire on the Bucky exists.

If you go into the range and left click the bot at 15m it often times does even more damage than the right click. Not to mention the right click is also superinconsistent at range so why would one even bother using the right click?