Well, you can exchange USD with oil, goods, services everywhere.
P2P payments can be successfully done in USD for few cents (eg. Venmo, Paypal etc..).
Anonymity is not a point because all transaction are public in the blockchain.I could pay in Monero to my fellow drug dealer but it's difficult to exchange it for a Ferrari without going through KYC.
There are a few websites accepting it. It looks to me that "paying with bitcoin" is the minor use case.
It's seems just a tradable stock that goes wildly up and down because it's impossible to find a reasonable fair value. The whole industry is based on trading, but the underlying asset is mostly useless. No dividends. No places to spend it. No low-volatility. No inflation-adjusted.