The importance of building silence into a VUI design applies to all three. It’s just as important as knowing when to use sound. Let’s look at the first tip: “Never accept the feeling that your sound design is significantly slowing down your experience.” Even when your design is faster with implemented sound design, it doesn’t necessarily mean that it’s needed. If it still detracts from the user’s focus and comfort, you might want to reconsider your creative decisions and build silence into a VUI design.
To emphasize your sound design, you need to make it more noticeable to make it more distinct, recognizable, and functionally useful. Therefore building silence into a VUI design is exceptionally influential because it creates contrast and prioritizes the user’s focus. It’s similar to using negative space in visual design; silence creates a space for other elements to receive attention.
In any context, sound should at all times elevate the conversational experience rather than detract from it.