There are so many benefits to giving your dog a stuffed Kong, or other food chew toy or activity toy. When you just put food in a bowl, typically either your dog will either gobble it up quickly or graze slowly which may lead to your leaving food out all day. In either case, there the opportunity for enrichment really is not there. And by leaving food out all day, your dog will tend to value it less (not to mention it makes house training pretty difficult). Think about these food toys as enrichment and trouble prevention.

To Have A Better-Behaved Dog, Consider What Happens Between Your Training Sessions
Every waking moment of every day and every interaction your dog has with you and the environment is teaching your dog what works, what matters, and what associations to have.