While true, simply day trading are the users ever going to withdraw the actual token?  Just like real world options, no one actually takes delivery of that option.  The exchange is just giving you an IOU in which you must trust they have your balance available.

Perhaps we need to divide this into two categories.  Trading tokens such as BitBTC vs BitGold.

Additionally, take a look at the deposit/withdraw page in the wallet.  With OpenLedger you can go direct from the Open.Asset to the real token or vice versa.  IE deposit BTC and receive Open.BTC which can be traded against other pairs.  When you think of the big picture these exchanges such as OpenLedger have motivation to compete for your business.