I have seen these used on the tv shows Chopped, Top Chef, and The Iron Chef several times. They are cool little tools which can impart a lighter smoke flavor to food. You are basically doing a quick cold smoke to impart the smoke and then cooking the ingredient its regular way.
Also to help with a smoke type of flavor they will put the cooked food in bowls and cover with plastic wrap and then pipe the smoke into it and seal it. When the person eating it removes the plastic the smoke wafts out and stimulates your nose with nice smokey smells which also helps with them tasting the smoke on the food.
*Weber Mini WSM* *Weber Touch and Go Performer X3* *Sublime Smoke UDS* *Maverick ET-732 * World's Fastest Blue Thermapen **Pitmaster IQ110*