It's competing with Banks!
Think about it...
Facebook has created a permissioned blockchain that hosts a stable coin.
A coin that they hope will eventually be used for every day purchases, just without the credit card mark up fees.
This kills credit card companies.
It also kills banks as many financial products will soon be done via facebook.
Need a mortgage, go through facebook?
Need to send money overseas, go through Facebook.
(Source: https://www.pymnts.com/facebook/2019/what-the-launch-of-facebooks-libra-means-for-payments/)
This isn't going to kill bitcoin most likely, it's most likely going to kill or severely impact credit card companies, banks, payment processors, and remittance services.
What does that mean for steem though?