Conversion optimization always boils down to one concept: Reassure people that your offer definitely concerns them and is the goal they are trying to reach. Every additional bit of information you add to confirm you have what they are looking for gets you closer to more conversions.
One of the best examples of that concept is the billboard advertising strategy the “South Of The Border” attraction uses on Interstate I-95. Successive billboards over hundreds of miles keep detailing what else they have: “Tamales,” and then a billboard reads “Tops,” “Mini Golf,” then “Flamingos,” and “Tequila” and so on. Sooner or later, they name something that’s for you and you have to stop.
That’s why callouts and structured snippets in search ads are so necessary.