i think amazon will integrate cryptocurrencies but i dont think that it will use bitcoin because bitcoin cant handle that ammount of traffic (fee will be too hight,transfer time will be too long) ,that being say we know amazon as the tech evolving company that expand in different domain that mean that it isnt going to stand by where there is huge profits to be made using crypto which will definitily boost her  stocks(which happened with kodak) so amazon using crypto will be one of two option:
1-partnering with a blockchain project(she wont be using bitcoin)
2-developping its own crypto currency