1) these hands are good for 3betting IP to a villain who folds to 3bets a lot and only 4bets a tight range therefore an easy laydown can be made and if he flat calls they play well IP and they can win big pots. They are also useful for set mining IP preferably the BTN when stacks are deep. Flopping trips, houses, big draws and disguised 2pairs.

2) I suppose your opponents have to widen your range which makes their decisions harder as you can rep alot more board textures. Also you may put your opponent on tilt by cracking a big hand of his which is very +EV.