It definitely is that easy. Strange can't help but give Yuya a confused frown as he mentions learning magic not being that easy because what, that's dumb.

"I—" oh, no wait, pause for a moment as the manor trembles and a piece of ceiling falls down a few feet behind Strange. There's a pause while he catches his breath before he continues. "A man under a hedge sold me my first spell. When I cast it, I had no idea what I was doing. Magic is that easy. It's simply a matter of practice and wanting to become a magician."

You know how when you're playing a sport and the person who's just naturally good at the sport has no idea why the person with no hand-eye coordination is sucking at it? That's Strange and magic. He learned magic fairly easily, so naturally others should as well!