The wallet is used to keep Wallet Funds, which are used for:

(sp)(sp)(sp)International long distance calls
(sp)(sp)(sp)Incoming 800 number calls

While not required, it is suggested to keep $1 to $5 in your wallet for international calls, otherwise each call will result in a charge to your account.

If you do not have an 800 number or do not need to make international calls, the Wallet does not apply to you.