This also works the other way around - 35.Nxf6 Rxd4 36.Rb8+ mates and it cuts out the defence 35...Rf8, otherwise it's merely transposing moves. Sometimes it's good to give the opponent alternative chances to blunder!

On 35. Nxf6, I would have thought Qxf6 36. Qxd5, Qxb2 37. Qxe4 and Black limits his initial additional material loss to a pawn and the exchange. Nothing to sneeze at but in my mind I thought I might gain more thru the immediate check since I had analyzed thru to the pawn fork though it is true that Rf8 is probably a better defense though somehow I instinctively knew Black would not exchange off his f file battery giving up his d pawn in the process. Perhaps those losses were more apparent to Black than the actual continuation -- for some reason Knight moves (and captures -or forks) are often overlooked it seems.

Is there a theme here, a message, a good lesson to be learned? Why was this game significant other than you managed to outplay what appears to be a significantly inferior opponent?

A lesson to be learned? Yes, for us folks of a lesser caliber. The reflected ratings are those at the end of the game, the ratings were closer when the game began - mine was lower, Black's was higher. I never consider any opponent to be significantly inferior (regardless of rating before,during, or after a match) = that is a judgement I reserve only for personalities.