The books are way overpriced now because it’s hard to get. Once we get more high level content, legendary books will be common. If you watch any KR streamers, you’ll see their inventory are full of them.
I suggest you get the cheaper skills one. Don’t go for Grudge legendary books, it’s not worth it for now.
Desirable legendary books still have value in KR.
They are completely unecessary now though to do any of the content in the game.
It’s just a longterm goal to attain and other content in the game will award more books.
You can gain additional Engraving effects from Accessories and Ability Stone, so once you have your formally 2x equipped Engravings at Rank 3, you can work on additional Engravings; eg if you had +12 natural Grudge from books, you just need any accessory to be +1 Grudge and you get it, even without it being equipped in your Engraving slots
This is an alarming mindset, nobody needs Legendary tier engraving books right now. I have 4 level 15 engravings on only purple books. For accessories, select an engraving that isn’t “top tier” and you will get well over 90% of the efficiency for a fraction of the cost. When vetting stats/engravings I really only look for a handful of red flags. What engravings and combat stats are you running now?
Why do people obsess (not talking about you OP but the people you are talking about) over engravings like that? I could understand if the content required every single player to min-max but it doesn’t so it’s just people basically measuring their e-peen and mocking others if theirs is smaller. Someone that has a competent build while not min-maxed is still going to be effective.
Online games sure can be the worst if you come into contact with some of the cretins that play them.