I would like to get discounts, tax exempt, wholesale, etc. Do I need this? What is it's purpose?
You may want to check with your state. Some states allow you to just use your SSN if your business is small enough.
I live in Texas and here you have to have it to shop in lots of places for wholesale. Also CK products, bakery crafts and some other sites require it. Check with your states comptrollers office.