Putting aside the politics of it all, crappy day to be a part of the Chinese American community with friends and family overseas.
EDIT: I wonder if we'll be able to get around these restrictions while traveling -- Visit Canada for a weekend, download WeChat, and come home? Android users can just sideload apps in any case.
This order does seem to prohibit any [US] business from accepting WeChat pay or otherwise using WeChat for their services.
If you want to talk to someone in Mainland China, your option is pretty much only WeChat