Grimoire shows how much the player has bought into the game. If you have a high grimoire score it shows that you have taken the time to complete all of the achievements, people are correct when they say it doesn't make you a better player, however I will say this there is NO skill in any subject that isn't improved by practice. Yes some of the score is for finding hidden objects and to some this is a mundane task, some is for killing enemies - here comes the practice some is for obtaining certain weapons - harder activities therefore more practice. So yes you are correct it doesnt mean a player is a better shot, however it shows the player has played lots and therefore has practiced lots and experienced most if not all of the content depending on the grimoire score. I for one recognise the accomplishment of those players with maxed grimoire scores for they have achieved something not many in the game have!! Only lazy players whine and say it doesnt mean anything. If you truely do not care to do it you probably wont whine either because its irrelevent to you. So lazy ass players stop whining!