Stablecoins are 'connected' or backed by something, typically a fiat currency and commonly the US dollar.
This provides a more familiar investment if institutions, especially given the amount of negative press FUD 'they' publish about cryptos.
It seems the Empire is striking back, by looking at these coins as a security they must come under the SEC and other rulings as must their providers.
So stable coins will probably switch to another backing currency, or perhaps disappear altogether.
Perhaps it is time for cryptos to become gold backed, thereby avoiding the US 'rules' and perhaps even those of WMF.
Time will tell
https://www.coindesk.com/will-fiat-backed-stablecoins-pass-legal-muster-with-the-sec-and-cftc