Could you explain this punch line?

A guy walks into a bar with an Ostrich
A man walks Into a bar with a full-grown ostrich behind him. The waitress asks for their orders. The man says, “A hamburger, fries and a beer,” and turns to the ostrich, “What’s yours?” “I’ll have the same,” says the ostrich.
A short time later the waitress returns with the order. “That will be $18.95 please,” and the man reaches into his pocket and pulls out the exact change for payment.
The next day, the man and the ostrich come again and the man says, “A hamburger, fries, and a beer.” The ostrich says, “I’ll have the same.”
Again the man reaches into his pocket and pays with exact change.
This becomes routine until, the two enter again.
“The usual?” asks the waitress. “No, this is Friday night, so I will have a steak, baked potato, and a shot of Tequila,” says the man. “Same,” says the ostrich. Shortly the waitress brings the order and says, “That will be $20.” Once again the man pulls the exact change out of his pocket and places it on the table.
The waitress can’t hold back her curiosity any longer. “Excuse me, sir. How do you manage to always come up with the exact change out of your pocket every time?”
“Well,” says the man, “several years ago I was cleaning the attic and found an old lamp. When I rubbed it a Genie appeared and offered me two wishes. My first wish was that if I ever had to pay for anything, I would just put my hand in my pocket and the right amount of money would always be there.”
Awesome says the waitress. “Most people would wish for a million dollars or something, but you’ll always be as rich as you want for as long as you live!”
“That’s right. Whether it’s a gallon of milk or a Rolls Royce, the exact money is always there,” says the man.
The waitress asks, “But, sir, what’s with the ostrich?” The man sighs, pauses, and answers, “My second wish was for a tall chick with long legs who agrees with everything I say.”