Proximity to heat changes the flavour of your food. Too hot and you will scorch or at worst set fire to whatever you are cooking. Not hot enough and it wont cook. Learn to master the temperature control of your grill and create different temperature zones.
Kamado allows you to cook at a wide range of distances and cooking zones simultaneously.
Sear meat by creating a direct zone, have a heat deflector on one side to create an indirect zone for keeping food warm or just slowing the cooking process down.
To roast or cook, long, low and slow use both deflectors to create an oven type environment.
With the lid on this creates an oven type effect and allows the heat and flavours to recirculate. It also helps prevent flare ups.