One cannot look at a sequence of moves and say, "That performance is 2039." Performance can only be inferred from wins, draws and losses.
A further assumption is necessary, because chess performance in the above sense is still not measurable.
The lower rated player will also gain a few points from the higher rated player in the event of a draw.
This means that this rating system is self-correcting.
On the other hand, the computational simplicity of the Elo system has proven to be one of its greatest assets.
With the aid of a pocket calculator, an informed chess competitor can calculate to within one point what their next officially published rating will be, which helps promote a perception that the ratings are fair.