I suppose bad rankings is the better term for it then lol. Riryoku and other bad cards in PvP are rated very highly while others that are actually good are rated poorly. Idk who decides the rankings on this site but they definitely do not play this game
Oh that's an easy one: It is because all Initial Ratings, the ones the go up first, are rating for PvP (even tho still sometimes incorrect). Then, IF a second one is made, it is meant for say Farming or AutoDuel because there isn't much of a PvE in DL. Add in your last sentence and we have Game A's Rating System.