On Chris Coney's post today, https://steemit.com/cryptocurrency/@marketingmonk/mlhoryuj there was a comment from 
Doesn't Coinbase already trade against USD anyway? why would they need to have a coin that is pegged to USD?
As my reply got longer and longer, I realized - I really needed to just make this a post by itself.
There are several reasons -- not only
Chris' (
) reason about not needing a dollar bank account, but also
You can instantly transfer USDC just about anywhere that hosts USDC. Poloniex, I believe was the first, since it's Circle's baby (Goldman Sach's baby), but OKex, Kucoin, LAToken, FCoin and others are places you can trade cryptos against USDC. And the list is growing -- Just go to CoinMarketCap.com, search for USD//Coin (ooh, what a name!) and click on Markets.
Compare this to trying to transfer USD anywhere - say "oh the fees" in the same way Dr Smith said "oh the pain" in Lost in Space.
It gives government an actual way to track FIAT
It gives government an ACTUAL argument to say "why do you need that stupid volatile fake crypto money NOW? Well, punk? Why?"
We can trade USDC against USDT and make money if it demonstrates amazing volatility, if we use the right tools (algo trading, TA)
We can trade USDC against BTC and make money if it demonstrates amazing volatility (algo trading, TA)
For Coinbase (and anyone who hosts it), it gives them free assets that make them look good. People deposit actual cash or crypto to them in exchange for USDC. Now Coinbase has an asset on the books, which makes Coinbase look bigger ("hey, look, we have 4 billion in assets, wait, no now it's 5 bill.. 6 bill, oh never mind, it's 20 jigittybillion").
Because Coinbase also owns Coinbase Pro (formerly GDAX) and some traders will flock to use a "stable" USD-based hedge instead of USDT, they'll be able to trade against all the new ERC-20 tokens coming soon, PLUS the STO's (Security Token Offerings) that will be flooding the market in 2019 once SEC clears things. Rest assured they have paved the way for their buddies who run the financial markets.
Don't think traders will flock to Coinbase Pro? That's fair. What about all the new wanna-be traders? All the 25 million Coinbase users (remember how Coinbase just celebrated their 25 millionth user?) who pretty much automatically can get an account? "FREE TRIAL" + "WHEN MOON" + "ONLY 21 MILLION BITCOIN" = FOMO CITY.