Method to learn scales on mandolin?

Excerpt from the original

I just saw a video that left me a bit bewildered. The video was about learning major scales in all different keys on the mandolin. Now my method would be that: Start with the tonic, so if you want to play C major, start with C. Go up one octave (or two octaves). Go back down to the tonic. Maybe, if you are a beginner, sing out the names of the notes, or just say them, to become aquainted with them. Maybe write the scale down, so that you learn reading and writing sheet music. if you will dwell longer on your scale, maybe add exercises along the scale, add triad, sixth chord, fourth-sixth-chord, dominant seventh chord. and go around the circle of fifths, so that eventually you will have studied them all. However, this video had another approach. It recommended to play all the scales in one go (why not), and to go around the circle of Fifths counter-clockwise (why not?, but also why?). The surprising bit it is that the video recommended not to play one octave or two, but to go through all the notes in first position. Start with (lowest possible) tonic, go up to 4th finger on E-string (B or Bb), go down to G (empty G string) and then go back up to tonic, but instead of play