The concept of being able to charge your Eye of Ayak while fighting the Doom of Mokhaiotl has been very well received, and created an additional incentive for fighting the delve boss other than simply collecting it’s uniques. I believe the game would benefit from giving the Serpentine Helm the same treatment.
It simply adds an extra benefit to visiting Zulrah every so often, and making use of that daily resurrection you got from the elite western province diary. It also lowers your supply costs, if you opt to avoid being envenomed with the bosses helm instead of antivenoms.
So why allow the serp helm to do this, but not the other chargeable weapons it drops? I’m not opposed to those items being chargeable as well. The helm just feels the most appropriate, because it’s tied directly to your supply costs for fighting the boss.