These threads usually don't have longevity because of the political charge associated with elephant ivory. Obviously, I'm fine with it because I do own two knives with it. One is a Protech Stinger and the other is this GEC French Kate.
From what I've read about elephant ivory is that it checks over time, yellows and mellows, but responds well to mineral oil. It's different than bone in that it has a creamy, streaked appearance. It also has a warmth in the hand that is different than bone. Nothing quite compares to real elephant ivory..... at least nothing that I've come across.
As to its sturdiness on a knife handle, I don't know for sure since I haven't carried mine, but I would say it's safe to assume that anything short of heavy duty or beater usage should be fine. Elephant ivory was extremely common on knives in the past and I don't think makers would continue to use it if it wasn't fairly stable. Well, unfortunately, they can't continue to use it here.
I will say that elephant hide is extremely durable. I have a wallet and a belt keyper made from it and they look as new as they did the day I bought them, 5 years ago!
Enjoy that mammoth ivory and ignore the haters and complainers!