Sniffing is the most mentally stimulating activity for a dog. Sure, walks are important for exercise, but dogs aren’t reaping all the benefits unless they're allowed to sniff as well. A dog getting mental exercise is just as important as a physical workout.
This kind of walk means letting your dog take the lead and follow their nose wherever it wants to go. Obviously, you're there to keep a hand on their leash and make sure they don't eat something they shouldn't or wander into dangerous situations, but your allowing them the freedom to check out new smells. Let them sniff for as long as they'd like and allow them to choose what direction to go as long as it's safe to do so.
These adventures in smelling leave many dogs more content (and even tired) than after a walk when they are moving all the time without the opportunity to take it all in through the nose. Using their sense of smell is incredibly enriching for dogs, and their brain is processing so much information that it makes these kinds of activities an excellent way to burn excess energy.
Most dogs want to take in the smells on a walk and explore based on what odours are around. Being constantly prevented from doing so as people urge them to keep moving can be very frustrating for them and robs them of the opportunity to follow their noses.
These unstructured walks in nature where your dog is free to sniff and explore aren’t only stimulating, they are decompressing and stress relieving. Its also a great style of walk for dogs who are visually impaired as they get to experience the world through their nose.