If you decide to expand out to the Grand Opening Party, you'll receive a building with a population allowance of 1,600 citizens. It can be collected from just as you can collect from other Community Buildings, but when doing so, you'll also have a chance of earning Golden Tickets for your Famous Businesses.
Ultimately, expanding out to this Grand Opening Party is voluntary, and you can continue to expand in other directions if it simply doesn't interest you. If, however, you're looking to complete your Famous Business collection, or even the Famous Mall, it couldn't hurt to have this item on your "side."
Will you expand out to the Grand Opening Party building? Sound off in the comments!