This feature allows you to set the Woo Braintree Payment to work with your production Merchant ID and API keys. Comparing with the Testing on Sandbox which allows you to make test/fake payments in this mode the payments are for real. This is the mode that you want to use in order to allow your customers make real payments for real goods and services you sell.
Likewise the Sandbox environment this one also has its own Merchant ID and API keys so after you switch in this mode you have to enter the production environment credentials.
It is important to test your production account with a couple of low-value transactions using various payment methods and allow the transactions to settle. The funds should successfully make their way into your bank account a few days later.
The production environment only works with real payment methods, so those used in the sandbox will not work. This means that any test transactions that you allow to settle in production will actually take funds from the payment methods used, and you’ll be assessed the applicable transaction fees. So, be sure to use reasonable values and run a limited number of transactions.