Are there any bonuses for a Supremely Trained Pokemon?

Is there any reason to finish all the Super Training regimen including the secret training, to make my pokemon a supremely trained pokemon?

I know secret training gives you items/stones, but is there any bonuses to the pokemon in doing so?

Solution 1:

Every Pokémon has something called Effort Values, or EVs. Each Pokémon has up to 510. 4 EVs amount to one stat point greater at level 100. I can explain this in more detail if you would like.

Once a Pokémon has maxed it's EVs, it is said to be "Fully Trained" unlocking the Secret Super Training regimes.

When you complete all of these, which are much harder, the Pokémon is said to be "Supremely Trained." The only long term benefit of this is to show it off. Short term, you do receive rare items, such as evolutionary stones, by completing Secret Super Training regimens.

Aside from the fancy symbol next the Pokémon's name, you get nothing. There are no other possible (permanent) stat boosts in the game. Poémon-Amie lets your Pokémon shrug off status effects and survive potential KOs, but these traits are limited only to Pokémon-Amie, and they do not carry over to competitive play.

Solution 2:

Completing Super Training

Pokémon that have earned a medal in each Super Training event can receive a 'Training Ribbon' for their efforts.

From Serebii:

Training Ribbon:

• Ribbon that can be given to a Pokémon that has overcome rigorous trials and training.
• Show a Pokémon who has gold medalled every Super Training event to man in Lumiose City café

From memory, the café you're looking for is Café Ultimo, on the Northern Boulevard.

Completing Secret Super Training

The only benefit you receive from Secret Super Training is the items you can receive. Once you ccomplete the last challenge, you will be told that the Pokemon is 'Supremely Trained', but there is no Ribbon or additional benefit for Supremely Trained Pokémon.

Its also worth noting that if a Pokemon loses its EVs it doesn't lose access to Secret Super Training. (Bulbapedia)