True, but the U CAN DO is not your typical 3D plane. It is extraordinarily stable on low rates. Other than the limited self righting characteristics of a trainer, the U CAN DO is every bit as stable as any trainer except maybe a Kadet SENIOR. I would not try to train with an aerobatic scale plane like an Edge, Extra, Giles or Ultimate, Pitts, etc. They are prone to stall at lower speeds and are generally unforgiving with excessive elevator or rudder input at the wrong times.

That being said, any relatively stable plane that lands easily is fine for a trainer, provided that you learn from a good trainer with a good thorough training plane, and you learn on a buddy box. Trainers are ideal, but there are most definitely other planes that are not classified as "trainers" that will get you well suited to competently fly solo and safely allow you to skip the expense of a trainer and move to a plane that will perform better overall once your skills improve and you can crank up the rates.