I mix it with kibble at least once a week for my picky eater. I am just sure to make sure the ingredients are just the fruit/veggy or whatever. I never buy the ones with colors added, or preservatives. I asked 3 vets, 2 breeders, tons of research and trail test and both my GSD did fine. Stay away from banana unless you are trying to get them to poop!
Mine love squash, carrots, peas and the chicken withs veggies one. My oldest is very picky and will not eat for days (which leads to throwing up stomach acid). He's only 7mo old and already is snobby about food (I tried many diff kibbles to see if that was the issue before trying the baby food idea).
When my Maltese was sick, my vet suggested giving him beef baby food when he would not eat the boiled chicken and rice. While that worked fine for a Maltese for a couple of days, you would have to feed it by the case to a GSD.
High quality dog food is "goodness". Someone at the dog food company put a lot of thought into a dog's nutritional needs. Randomly selected human food or human baby food, might or might not be "goodness" for a dog, depending on what you are choosing and how you are preparing it.