Decorations are a useless way to waste Gold and Elixir – NOT. They do not have any use like a building, but they prevent attackers from deploying troops on a particular spot and they also make troops go around. You can use them to make enemy forces (best are Archers) group together and allow splash damage buildings like your Wizard Towers or Mortars to take them out. I have re-worked this post with new images to show you how this works. Hopefully afterwards you will go to the shop and get yourself some nice decorations for your base.
How Decoration Funneling Works and Why Decorations Are Useful
Even if decorations have no real use, they are buildings so troops are forced to walk across their outline instead of just walking directly through. In general (for example some Archers, but this also works for Barbarians and other troops) you will deploy them widely to protect them a little bit from Mortars and splash damage:
You should now surround your outside ring with Decorations (or like posted here with Obstacles) – you can see this here:
Now the attacker has no choice but to deploy their troops behind the Decorations. Most attackers aren’t even aware of what will happen next because they just don’t know, or they just have their mind on your resources:
The Archers, in this case, will walk between the Decorations to get to their desired target. Even if they get deployed in a row, they only have a few paths available so they will group together no matter what. After they come through the Decorations, they are now handily grouped together and your Mortar is waiting for them:
This will save Mortar projectiles, and the Archers will drop like flies.
It was difficult to find a base to take screenshots, but I think you get the idea. To make it perfect you will need to have the Decorations directly next to each other:
The Archers will group together even closer and have almost no chance of surviving. Instead of destroying all the outside buildings with a few Archers the attacker has destroyed very little and has lost most of his troops.
Obviously you can’t build that kind of ring around your whole base, but if you close some sides you will definitely see an impact. Be sure to purchase the cheap Decorations so you do not have to invest that much. I hope to have made it clear that Decorations aren’t useless at all. Be sure to watch out yourself for Decorations – someone might just funnel your troops
Thanks for editing: EnchinsuOcha, JamesM, MikeO