DRII
G.O.A.T.
Yes that's very important for year end raniking, and its also 1500 ranking points for the next year.
And I find it interesting (and surprising) that the Master cup prize money for the winner was equal to the USO prize money for USO winner, at least in 89. It shows how important this tournament was for the players.
uhm no

it shows how unimportant the tournament (YEC, WTF, Master's Cup, Elite Exhibitionary Event, etc) relative to the slams overall. the WTF has been knee deep in politics since its inception, whenever you want to decide it actually started. resulting in a vast array of inconsistencies throughout the events history! the ATP had to offer huge prize money and points (and lavish circumstance) to try and ensure that the players would show up at the end of the year and not compete in other like-minded tourneys in the past.