what needs elaboration?
For the sake of the argument, Corneria's fin is a building and so are the blocks on Green Greens. Essentially just rewriting what I wrote above:
Corneria is less stupid because Fawks retreating to the other side doesn't put him back behind a building to camp again. It also has a ledge that can be grabbed to gain invincibility frames to utilize on your approach. It also isn't right next to the edge of the stage so you can jump out off the top of the building outwards without being at risk of immediately dying to a move with horizontal knockback.
Green Greens is less stupid because the building is destructible which lets you create a horizontal angle of approach as opposed to a vertical one where you need to compete with Fox's stupidly diverse and powerful arsental of upwards attacks (usmash, uair, utilt, bair).
For the sake of the argument, Corneria's fin is a building and so are the blocks on Green Greens. Essentially just rewriting what I wrote above:
Corneria is less stupid because Fawks retreating to the other side doesn't put him back behind a building to camp again. It also has a ledge that can be grabbed to gain invincibility frames to utilize on your approach. It also isn't right next to the edge of the stage so you can jump out off the top of the building outwards without being at risk of immediately dying to a move with horizontal knockback.
Green Greens is less stupid because the building is destructible which lets you create a horizontal angle of approach as opposed to a vertical one where you need to compete with Fox's stupidly diverse and powerful arsental of upwards attacks (usmash, uair, utilt, bair).