The ability to create an asset, distribute pieces of it to various parties, then pay distributions/dividends on profit or income to the pieces of said asset, as shown in this video:
https://www.youtube.com/watch?v=eyzA5Lj1ajMDividends may even find a (perhaps unintended) use as address alias. Say I create a token called MYNAME. I issue only one share and keep it to myself.
Instead of handing out my bitcoin address, I tell people my asset name instead. It is easy to remember and to type in. To send me bitcoin you need to pay me a dividend. Right now that's too practical, but say that a wallet program automates this.
For example, in the "Pay to" field in Electrum you could insert either an address or a token name. Perhaps the token name could be of format [TOKEN]@XCP. This would truly make bitcoin the email of money.