Can someone explain to me why Altered Flesh is good?

Been doing some Googling and there doesn't appear to be a very good answer on why Altered Flesh would be desirable.

I understand that if you stack maximum fire resist you can gain a bit of elemental survivability, but it's marginal at best. An extra ~5% damage reduction (only against cold / lightning)?

The physical to chaos conversion seems downright horrible considering how difficult it is to cap chaos res. If I'm not mistaken chaos damage is doubled against energy shield, so if you have any ES on your character, that's actively bad.

On top of this, at level 30-40 when you first get this node, there's a 100% chance you'll actually have zero chaos res...so this is actively a downgrade until deep into the endgame as far as I can tell. Yet we're forced to take it early on. Meanwhile other classes are getting massive boosts from their 3-4 ascendency points.

What am I missing?

1/5 of dmg Cold and Lightning gets taken as Fire Dmg, so if you have decent fire res then it wont matter and same applies to chaos res

If you have any decent chaos resist it applies to physical.

If you have 0 armor and 75% chaos resistance, then 100 phys damage would become 80 phys + 20 chaos (which would be reduced to 5), totaling 85 damage. Chaos damage does double damage to ES, so it would go to 90. That's a 10% phys reduction, which is not astronomical, but is relevant.

TLDR it’s good get it.

Chaos Inoculation says "hi".

But yes, at the exact time you get access to that node, it's not necessarily very good. But it gets better and better.