No, it's not necessary to use a PayPal Business for WordPress. You can use your personal PayPal account to accept payments in WordPress. However, some WordPress solutions require you to have a PayPal Business account. For instance, you need a PayPal Business account if you're accepting payments for your WooCommerce store. Similarly, PayPal Commerce also requires a Business account to work, but you can still use PayPal Standard with your personal account.