No, it's not required. The bigger question is why wouldn't you want to initiate a friendly hello or respond to a client chat after they chose you to provide care out of all the others? The chat feature was designed to create an immediate friendly atmosphere which helps lower anxiety. We recommend small and short sentences such as "Hi, can't wait to meet you Monday!" or "Hi, can't wait to care for you!".
Remember, responding to chats help show you are friendly, responsive, professional, and serious about providing care!