When you see somebody play that deliberately, you know they're learning to play it slowly and accurately, practicing that way for a while, then adding 1 or 2 bpm to the metronome. Lather, rinse, repeat.
Anytime you're making mistakes playing, you're not only playing too fast, you're teaching yourself to make mistakes. Then it becomes a habit that won't break because you're practicing doing it wrong, and that becomes the norm.
At least, that's what I've been taught by a guy who could almost do no wrong. Of course, you'd never know it to hear me play :laughing7: