The base features funneling with extra walls. So that it takes some time to destroy inferno towers. Centralized clan castle makes it hard to lure. Opponents have to take at least one cannon to lure cc troops.
Walls are the main fortification for defense and are capable of withstanding a great deal of damage from attacking enemies. However, upgrading walls costs lots of resource. Here is a chart to analyze how many resource will take to upgrade walls.