I though that, Coinbase being already licensed as a payment processor, a Coinbase customer already could
* deposit dollars at Coinbase
* buy bitcoins at Coinbase,
* withdraw his bitcoins,
* send bitcoin to a merchant
* have Coinbase send the dollar value of his bitcoins to merchants

With a money transmitting license, a Coinbase client can also
* sell his bitcoins to Coinbase (or other Coinbase clients)
* withdraw the dollars from such sales

I.e. Coinbase becoming a fully licensed exchange makes it easier for people to sell their bitcoins (not just spend them in purchases).  They could already buy bitcoins from them, so that part did not get any easier.  

Is this correct?