[He's both a Gym Leader and a Connoisseur of many many things. Multi-tasker to the stars, this one.]

Absolutely! The emotional connections between Trainer and Pokemon, the two working together in harmony to achieve victory--they draw out each other's strengths and can present a truly wondrous taste in battles! If there's no compatibility, then they can't bring out their more inherent flavors when tuning themselves to their Trainer's commands, and in turn the Trainer can't work in-sync with their Pokemon. That's why it's important to have a bond with your Pokemon if you wish to draw out their full potential.