I suppose this formula is successful in Japan; otherwise, they would have stopped using it. Personally, I find this type of work more interesting; at the same time, it's simple. The ugly character tends to be the antagonist, end of the mystery. In another work directed at a different audience, this might be a bit boring, but if it's a game of this nature, it means many good scenes for our enjoyment and a lot of work for Takeda Sensei lol.
Consider this: What would hurt you less, or what would you like more?
1- A group of three Korean idols stealing your harem.
2- The three antagonists of this game stealing your harem.
3- An extraterrestrial stole my harem.
Obviously, the answers will vary, but that's the idea. Enjoy fiction because reality hurts more.