In light of the recent portato question at What do the dots and lines underneath these chords mean?, what did Debussy mean by the tied portato on the third quarter note of the second measure of Debussy's La Cathédrale engloutie?
On one hand, portato on the piano indicates a slight re-articulation of the pitch. If that's the case, then why is there a tie between the two Gs, apparently telling us not to re-articulate?
The situation becomes stranger when we hear Debussy himself perform this (via a piano roll); he does not re-articulate this G.
What is the point of the dot above this G?