Does interacting with highlighted objects in Masyaf accomplish anything?
I don't think they impact completion stats, but they are easter eggs for those of us who beat AC1 and foreshadowing for future events in the game. They show some key stuff from Altaïr's genetic memory, as well as show that Ezio is suffering from the same genetic memory bleed as Desmond at that point.
Altair jumping through the window is seen in one of Altair's five memories.
I've finished the game 100% and didn't even notice those. So I would guess that looking at them is cool, but they don't impact on game completion.