The above URL contains the entire discussion. Below is a snippet.
Anyone want to weigh in on their pros and cons?
Helical lock washers have such a low spring rate that before they start to return you will have lost about 90% of the clamp load in the joint and if that happens, you have a failure going on. If they are fully flattened, then all you have is a hardened flat washer- so use one of those instead.
I would never recommend one at work and I take them off things around the house.
A waste of time and money and one more component that can be left out of the assembly.