Highlight is described as 'Have you ever been in front of an audience who wants a live demo instead of the screenshot/slides?'. There are 2 alternatives to Highlight for Mac. The best alternative is DemoPro.
DemoPro is a simple and unobtrusive screen annotation tool for the Mac ideal for live demonstrations. Just press a customizable hotkey to draw on the screen. Release it to continue your demonstration. DemoPro also includes a countdown timer.
Examples: - Add handwriting/drawings during slide presentation for better illustration - Add temporary notes on screen to mark documents of other apps - Outline objects on screen and keep the drawings for reference to use in another screen view - Simply doodle as you go