Accessory rank and Pheon cost

This game have different gear progression than usual, no steady increase when you get “better gear” instead it have checkpoints, more engravings, skill points, tripods. So legendary accessorys can have +3+3 engraving, relic can have +5+3 thats upgrade, but i really dont understand why need to pay more pheon for a +3+3 relic i get zero upgrade but i get rip off 10 pheons. And barely any usefull legendary in the market, everyone just pumping trash relic. And i know relic can go higher on stats but lets be real nobody care about that they just inspecting how many engravings you got, and they put 70k gold price on 10 quality stuff anyway… Its more reasonable if we pay more pheon for more engravings not for just a color, 15 is +3, 20 is +4 and 25 for +5 im stupid or make sense?