I think you missed the minus sign there and misread this, I will translate it: “The chance for rare loot to drop should be continuously reduced by 10% for every hour you log inside the game. I.e., you should receive rewards for completing difficult challenges rapidly, that is, skillfully.” The implication seems to be that if the challenge is hard and you are not good at it, and are just throwing yourself at a wall repeatedly, or the challenge is non-existent/mindless (chore simulator), if you are repetitively doing either and grinding hours away, they are one and the same, and neither is a meritorious achievement. I think this is an interesting angle, as very few games reward skill expression or eureka moments as a momentous achievement. The vast majority, genre and budget irrespective, rely on the (easier to implement) crutch of locking progression behind pointless tedium, so given enough hours sunk in, everyone can win. It is interesting to think about how, whether, and under what conditions games could reward the above.