Yea I know, especially considering you can't even use the scepter, sword, and shield.
I failed to mention in my last post that they're souvenirs. Sorry bout that.
Well, it's true that the sceptre, sword and shield are all souveniers, but the royal costume you get when you've donated 200,000 points shows up in your items list. Your adult tamagotchi can parade around in it. The souveniers and the royal costume do not disappear when your adult tamagotchi leaves, either.
When two tamagotchis that have both donated 70K or more points connect to play a game, there is 1000 points on the table for the winner, instead of the usual 400 points. If your tamagotchi gets a perfect score in whatever game they play, your tama wins 2000, instead of the 1000, so it can be pretty lucrative.
Also, once you reach the 200K mark, you cannot donate any more, period. This means even if your current tama grows up and leaves, and you are raising the next generation, that new baby doesn't have to donate anymore. He/she will play for 1000 points every time it connects with another tama that's donated 70K or more.
The more you donate to the king, the more letters you get from him, too. This means more presents and more points!