Apart from the obedience benefits of dog training classes there is another major factor. The dog will be socialised with other dogs and also with other people, this is most important with a young dog and lack of socialisation can give rise to all sorts of behavioral problems as the dog gets older.
A word of warning if using a Halti, do not rely on it completely to control the dog. Despite the claims the manufacturers make for the product, it is all to easy for an intelligent dog to work out how to remove it. One of my German Shepherds did this within hours of it been fitted. You can imagine the consequenses if the dog slips the Halti when out and runs off into traffic or to chase something. I always use two leads when trainig on a Halti.
Trainging classes should be compulsory for all owners as it is usually the owners that need training more than the dogs.