Voice based queries are on the increase. Those queries tend to be longer (longer tail is the industry slang). Coincidentally Google is rewarding (e.g. providing greater visibility) to sites that have the best content. Best content is considered that which answers all of the possible questions a reader might have.
For example, on my desktop I would search for “teal dress.” But when it comes to a voice query, I might ask, “Hey Cortana, where can I find a teal jersey knit cotton dress?”
By seeing what users search for via the Search Console (previously Google Webmaster Tools), a site owner can continue to modify the content to fill in the details that users seek, thereby making your site the best match for more queries.
Adapted from: Understanding Intent Through Voice Search