Why are poodles groomed the way they are
For the most part, Poodles were dogs that you would take on the hunt, and in duck hunting for example, the dogs would gladly go into the water to fetch them, and bring them to you. Much like the American Retrievers, and other hunting/retriever breeds, the Poodle was prized for going after things in the hunt.
The particular grooming of the coat was to allow the dog to swim easily, but keep the joints warm in the cold water and the cold weather. This is the most simple and historic reason.
Like most things, time and trends alter the “authentic” way, and the more stylized way the dogs are groomed, are to really show off the dog’s identity, the confirmation of the dog’s structure and indeed a fun and fancy way to enjoy the breed.
Research standard sized Poodles and you will see several popular coats and trim for the breed, all of which are fun and good depending on your sensitivities and proclivity for things beautiful. The dogs only care if YOU think they are pretty, so do the haircut that works best for you.