They definitely make things way easier but honestly, how many people playing dark mode will have the patience and money to make all these? If you ask me, it's not really worth it, especially if you want to feel like you're playing the hardest difficulty, you certainly don't need them to survive and likewise, you're not invincible with them, just able to survive more than say 3 hits. If you do want to get all 3 sets, amass a ridiculous amount of orens in chapter 2 before chapter 3 (after getting the second set if you want that), I'd say about 10,000 orens by chapter 3 and a fair amount of hardened and studded leather and robust cloth, cuz even though the diagrams are ungodly expensive, crafting them also costs plenty of orens. Unfortunately, there isn't much to use them on in chapter 3, so my recommendation would be to just get up set 2.
If you wanna make fast orens, arm wrestle. Seriously, idk if this works in flotsam but currently you get twice what you bet on top of what you bet in arm wrestling (so the dwarf in vergen you can wrestle for 35 orens, you get an additional 70 orens back wen you beat him, essentially making 70 orens per win), or you can just farm monster parts and sell them.