Nobody has ever explained whether Euron's horn does what he says it does

My maester tells me I raise this too often. My maester is welcome to raise something better.

The question, put plainly: whether Euron's horn does what he says it does. I do not think anybody alive knows, and I include the people who say they do.

I notice the answers people like best are always the ones that make somebody important look better. That is not proof of anything, but it is a pattern.

It matters less than the harvest, and I will still be arguing about it at midwinter.