but why this game getting much attention
For the opposite side of the same subjective coin you just tossed.
There are many reasons why people enjoy this game.
Some are unique & personal to the individual.
Some are more widely shared, such as the characters & the story having depth.
People don't just like Luna because she's attractive, they like her because her character has considerable depth. Same for the other main characters.
There are probably a number of people who share your view, too. Some don't bother wasting their time posting in the threads for games they don't enjoy. Others feel that their negative opinion
must be shared in the thread, inviting criticism of their opinion.
It's pretty clear which is the more productive choice.
And mini game that didnt effect to story? Really?
Some of the stories told in Contracts added more depth to MC's character, some added more depth to the DeLuca Family world.
Did you miss the part about MC's Father, in Nimble Fingers?
What about the considerable amount of Family lore in The Painter?
Weren't the Sisters, Amita & Amata, introduced in The Delivery Boy contract? They are now significant part of main story.
Wasn't Siobhan introduced in a mission, Rescue The Assassin, which used the new Contracts system?
Seems like a pretty major effect on the game itself, as well as the story.