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.