Review Detail of LightningCatThief in In The Whole World, I Have 50% More Rewards

So in the beginning I thought this novel had potential. The Cheat didn't seem too OP(I was wrong), the MC made some actually smart and careful decisions(that stopped completely somewhere after chapter 10) and the side characters seemed to have their own goals and thoughts(Didn't really change, thay just aren't relevant any more, except to boost the MC when it is convenient). So what went wrong? 1. The cheat became the motherload of all stupid loot boxing mechanism. The advantages keept compounding(Breathing technique to gain 1XP per level with no actual effort/time investment after level 10) and every other skill is literally pay to win. I have not a single clue why the MC is even training anything besides the necessary amount to gain control of his own body. Archery training is especially useless. 2. As mentioned above, the Breathing Technique is king, investing every available Exp in it is only logical and way more efficient than anything else the MC could do. It is not even explained why the MC stop investing after he rightfully recognized how important that skill is. It is just skipped out. 3. Story got a lot more monotonous and boring after the Side-Characters stopped being relevant.