For the keyboardist, a mastery of scales, arpeggios, and chords opens many doors. First and foremost is technique: the ability to play fluently and with virtuosity. The second door is the ability to sight read. The third door is the ability to improvise. Regarding scale and arpeggio fingering, one of the most difficult skills to learn is consistency. Source: The FJH Classic Scale Book. Thank you for listening.