I like that coin, too. Very unusual design. If you have several and stack them, the "teeth" hook into another and you cannot turn the coins like usual.
Also in the hand its pretty grippy. I used one to give up smoking years ago, by flipping it between the fingers when I got nervous.
I think they are even a bit collectable and sell over the usual coin prices. Fortunatly I have quite a few of them. Same as the 2 oz Niue Turtle, thats quite pretty, too.

Sending silver or gold in the mail abroad is not a good idea. There is a custom issue almost guaranteed. Or it gets stolen. Especially if you send it in a letter.