The bonuses would be the most important reason to maintain high trophy count. The loot bonus is already mentioned in a comment. Now we also have the star bonus, which is a more important factor.

The bonuses would be the most important reason to maintain high trophy count. The loot bonus is already mentioned in a comment. 

Now we also have the star bonus, which is a more important factor. Although you only get it for each 5 stars you gain in multiplayer battle, it is quite substantial amount. Also you will get dark elixir starting at lower leagues than you get with the normal loot bonus.