That was the first nocturne I learned and at the time, I found the left hand annoyingly difficult. Once I more or less mastered the piece, that rolling arpeggiated sort of left hand comes much more naturally to me, so I guess, in that sense it is a good left hand study - a la etude.
I love that nocturne and just about all of the others. I've recently come to particulary love the three posthumous nocturnes, particularly the c# which, oddly, is not in several editions of the nocturnes. I recently have started and the Opus 55, No. 2. I'm amazed at its depth and the fact that it never really grabbed me before.
I think the Scriabin d etude's left hand is much more difficult because of all the grand leaps. That piece is one my latest challenges. My son and are having sort of a tacit contest to see who gets it under our fingers first.
