It would make perfect sense, it would be a synergy if Amazon starts with it's own Crypto Exchange. It has been reported (by CNBC some time ago) that Amazon has gone out and registered some domain names that appear to be associated with cryptocurriences.
"A lot of speculation is being tossed around with regard to Amazon’s potential involvement in cryptocurriences going forward."
Source:
http://www.valuewalk.com/2018/01/amazon-cryptocurrency-exchanges/amp/
https://www.zerohedge.com/news/2018-01-22/could-amazon-be-gearing-cryptocurrency-exchanges
https://www.cnbc.com/2017/11/01/amazon-buys-crypto-domains-bitcoin-ethereum.html