God help us from Ponz's menace once he sees all these! I think I'm going to need a new bottle of wine! And quite a strong one!
The Ponziani is a draw with best play by both sides. The Ruy Lopez is a draw with best play by both sides.
I looked up percentages for theory for the first 6 possible moves in both openings. The results were White wins 48.2% with the Ponziani and 43.1% with the Ruy Lopez. This was 365Chess data base.
Of course this one stat means very little except that both the Ponziani and the Ruy Lopez are playable openings. Both openings have parts of theory where the position is equal and the game should end in a draw with best play for both sides.
One advantage the Ponziani has over the Ruy Lopez is that with the Ruy there is about ten times more theory to learn. Another advantage is few people are prepared to meet the Ponziani.
I am not saying the Ponziani is superior to the Ruy. They are close to equal but if you know the 10 times amount of theory in the Ruy--it has a slight edge.
However both the Ruy Lopez and the Ponziani are not quite as strong [in theory] as 1. c4.
White wins two pieces for two pawns and is lost in 11 moves - that's quite some game!
What should white have played after 9...o-o?
That whole line is very complicated. With best play by both sides--the game will end in a draw. But both Black and White must navigate through a quite complex series of moves. Of course if you play the Ponziani--there is a chance you will have a better understanding of the complex complications.
When the game was played the theory of that variation was up in the air but I took the Black side in several games just to learn and make the theory.
Best to avoid the whole line unless one is willing to learn the very complex theory.
The mistake in the game was 12. Qa6. Up until that move--the game should end in a draw.