Clash-of-clans – The search is very slow in Clash of clans

It is a bit weird at first - the destruction of your base only yields a hunk of your resources being stolen. Repairing your base takes only a few seconds and costs very little.

The overall goal in the game is pretty murky. There are ever-increasing base upgrade goals to be met, which you will gain either by waiting for your own resources to collect, or more quickly by raiding other people's bases. Pride in your town's strength and building levels could thus be considered a major goal of the game.

However, I would argue that the overall goal is to rank highly in the player-vs-player leagues, which require you to amass tons of trophies by successfully attacking other bases or defending your own.

Besides the rewards you already mentioned, there is a bonus for every raid you win that is based on what league you're in. It's usually small, but it can make a difference.

There's also the same reason there are leaderboards in any game - to see how you stack up against other players!

There is a downside to having many trophies, and that's that trophy count is an important factor in matchmaking. Thus, if you have many trophies you're going to get raided often by high level players, and you're likely to get matched up against hard opponents.

Many players that I've seen will try to maintain or lower their trophy count in order to find easier players to raid. You've probably seen players dropping trophies in this manner - usually, they will deploy a single troop against you, or they'll put out and immediate recall their hero units.