You write "zon" and mention lightning fury, so i assume javazon.
Well, it's a fine line. If you have the high-end gear, including cta and all that, you will probably have 1500+ hit points and max resists. With javazon being a high damage character, it should not be necessary with a valkyrie. Your merc should be enough. You will just have to adapt the style a little bit in how to deal with lightning immunes. But again, with high-end gear, i do suppose that infinity will be used, which as far as i can figure out, will break almost all immunities. Only two monsters according to this list, is the megademon/pit lord and skeletal mage/horror mage:
https://diablo-archive.fandom.com/wiki/Immune_Monsters_(Diablo_II)#Lightning_3
but here it says all forms of megademons have 75% lr, so i don't know
http://classic.battle.net/diablo2exp/monsters/act4-megademon.shtml
Either way, IF using high-end gear, it should not be necessary.
If using mid-range gear, then i would use it, as you would most likely not have more than ~800 hit points, mediocre resists, and using a lower resist wand for particular monster packs. Then you might need more time to apply lower resist and control the battle.
20 points should always be a staple on valkyrie. Even with 20 points, it is not invulnerable in hell. Only after 25-30 points does it really begin to get tanky.
The d/a/e thing i find is not a problem with javazons.. you are mostly attacking from range, and especially in hardcore, should be careful about going melee using charged strike. I've never found it to be a problem, more a benefit. At least avoid; Ranged attacks. I usually place a few points in that at least.
So it would decrease your damage a bit.. but unless you are one of those reckless people that don't care or play for fun, and just rush through hoping not to die, you should focus a bit on defensive strategy.