Power
So you want to be a big macher, eh?
You have the power of religion behind you. While rabbis aren't priests—that's reserved for the Kohein descendants, often with the Cohen surname—they are considered the teachers and the spiritual leaders of a congregation.
However, you don't have to have a rabbi to lead a service. Any well-informed, savvy Jewish person is allowed to do it.
You also have the power of prayer behind you. You're the person that people seek to bless the sick, injured, or dying.
When you mention rabbi in certain places, it comes with a form of prestige and respect from the average Jewish person. Including "rabbi" with your name on guest lists is sure to land you a nice table at Jerry's Deli far away from the restrooms.