Pardon the naive question, but does this mean Coinbase users who held Bitcoin have essentially "doubled their money"?
Also, people who just had money sitting around in a private wallet on the blockchain—that is, outside of any exchange—have also 110%ed their money; there's nothing special about Coinbase, it happened for any and all BTCs that existed on 2017-08-01.
(What is special is the accounts at the other exchanges, who have thusfar mostly not provided their users with access to their equivalent BCH gains. It can be argued that the gains were made to the exchange's float, rather than to the users' accounts, so the BCH isn't "inherently" owned by the depositors, any more than capital gains of leveraged investments using a bank's liabilities are owed to the depositors of said bank. Really, since this "debt" has no (legal or smart-) contractual existence, it's up to social norms whether individual exchanges capitulate and hand over the BCH gains they've accrued.)
I can imagine Coinbase held out on offering trading - if everyone wanted to cash out then Coinbase suddenly had to come up with millions of dollars that didn't come in through normal purchases of e.g. bitcoin.
IMO, bitcoin cash was generating valuable cryptocurrencies out of thin air.