Some reasons why XCP has value:I would like to add two more points:
1) Trading with XCP on the distributed exchange is (and always will be) cheaper and faster than with BTC.
2) You can use only XCP for making bets, CFDs and asset callbacks. Forthcoming complex features and financial instruments will also likely be restricted to denomination in XCP.
3) All future proof-of-stake voting, e.g. for protocol changes, voting functionality, DACs, etc. will be determined by XCP holdings.
XCP is the native currency of Counterparty and its sole first-class citizen. If the Counterparty protocol has great value (as I’m sure that it does), then so does XCP.
 XCP is also valuable because of the Counterparty Protocol’s ability to migrate to a different blockchain if needs be. I.e. if Bitcoin fails, Counterparty does not necessarily fail.
 XCP supply is truly deflationary as a certain amount of XCP is burnt (irreversibly removed from circulation) for various functions.
What price would you sell your XCP at? Personally, with the recent Medici Project announcement, I will likely never sell my XCP.