If responsible for a presentation, it can be a good idea to have a glass of water handy. Sometimes when speaking,throats become uncontrollably dry. This can lead to hoarseness, speech difficulty, coughing, and other quite visible discomforts.
Having a glass of water handy and taking a sip can overcome the problem and alleviate the difficulty.
The water may not be used, but it’s a handy insurance to have. You don’t want to be remembered as the presenter who coughed and spluttered all over the place.