I was just wondering if there’s a difference in performance or if tiles are mainly for convenience.
I’m making a Mario game with breakable bricks and am wondering if it’s worth using tiles where the player can’t get to the brick or if it doesn’t matter.
I’d say that if there are breakable bricks, and he can’t get to them, it sounds like a problem. 
Tiles are good to break up large images. If some parts of the large images don’t need to be displayed, the tile system allows to not load them, and thus offers better performance, logically.