If you're like me, a less technical user, the answer is that you can sell them for BTC or other asset:
XBTC:
https://forums.counterparty.co/index.php/topic,160.
Gold:
https://forums.counterparty.co/index.php/topic,179.msg1219.
With a little bit of technical prowess you can:
Create your own altcoin that functions within the rules you specify.
Create a callable, debt based asset.
IPO a company. The easiest example is if you owned a mining pool, you could distribute shares to all the miners, then automatically pay dividends in bitcoin, instead of doing it by hand with an excel spreadsheet.
As the system fills out over the coming month or so:
Make simple Win/Less bets (sports), or more complex financial bets, which will allow you to leverage or hedge your position in various currencies.
Please keep in mind that if you are in the USA or selling any of your cool Counterparty-based products to customers in the USA, you may be investigated by the Securities and Exchange Commission (SEC) for the illegal issuance of company shares for sale to US citizens or residents and/or the illegal hosting of betting platforms for US customers.
I don't like these rules anymore than you do, but please take note of the rules and regulations in your country. You can run a successful betting platform on Counterparty, you just may not be able to have US customers.
See Erik Vorhees problems with SEC:
http://trilema.com/2014/interacting-with-fiat-institution-a-guide/