No you don't need a permit to ship BP's. However to ship directly through FedEx you have to be certified.
There are a few benefits of becoming a licensed business. The 2 biggest ones in my opinion are tax purposes and legal reasons.
You can still claim expenses on your personal taxes without being a licensed business, but when we sat down and talked to our accountant there were still additional tax benefits with us becoming a LLC.
For legal purposes once you are a licensed LLC or Corp., it greatly reduces the risk you can face as an individual. If something were to happen you cannot be sued personally they can only sue your business.