Honestly they have to right ?
They cannot deny that if its get bigger they are having to accept it due to the fact otherwise there will be sold less more than normal for sure.
Accepting the bitcoin will also boost Amazon but also the bitcoin will have profit from this.
If Amazon began accepting bitcoin it will create in my opinion a big boom and boost to bitcoin because we will have access to all those products and services of Amazon
I don't think that amazon is going to accept bitcoin. Because they are just running about the profit and they are not going to risk it.
Because they know that bitcoin is a currency without stable price and they are just thinking about more the decrease rather than profit.
That's why gift card is just a good substitute for it.
Not for this time well if bitcoin is already becoming a mass payment I think amazon will never refuse that and forgetting about this the fact that is just a speculating and your ending sentences are true gift card is good substituted for bitcoin.