Oh I see it make sense then
But what makes people think that the company that created those Physical coins don't have copy of those private keys anywhere ?
You can't really know. However, these coins are not meant for storing Bitcoins and thus your question is irrelevant.
They have historic, artistic and material value. I have only a Kialara coin and it is great. Just because you do not appreciate physical Bitcoins (who knows when this trend would have started without Casascius coins), that does not mean that their value is not there.
People are paying millions for other things that should not even have a artistic value as high as they do.
$75M for this. Physical Bitcoins in comparison aren't even that expensive. There are coins made of various materials, and coins that have been graded and ones that have not. Everything contributes to determining their price.