Good news! Touchscreen gestures are supported in Storyline 360 and Studio 360 HTML5 courses on tablets and smartphones.
Swipe left and right to move between slides. Pinch or double-tap to zoom in and out. And drag to pan and scroll.
HTML5 gestures are automatically enabled, so you don’t have to do any extra work. (In Storyline 360, you can turn swipe gestures off on a slide-by-slide basis if you don’t want learners to swipe between slides.)