We don't know if people will use the Libra coin or not because this coin hasn't been released yet and still cannot be accessed by investors, the coin is still in the process of forming both from the system sige or other aspects, so we can't decide if the coin will be used or not
Libra is designed for people to use, so even at this development stage we already know how to use it.
and to answer @op's question, I think it will only be used by people getting a contract to launch their ads on facebook.
Or maybe the facebook influencers that Facebook pays for their video and much more.
I'm just hoping that libra will come true in which it's been too long since they've been started. Many of us will benefit the libra project because most people around here in the community already know and use the facebook and it will definitely each of us can easily to learn the benefit of libra coin here in crypto currency community.