>>1927>For example if you want to buy something with bitcoin but the seller only accepts ethereum, why cant you just go to an exchange and get what you need
That's not really the point, but you could make a contract that checks the current rates of things in a trustless manner and perform the exchange for you.
In the example of a decentralized exchange, the smart contract(s) responsible for the exchange could manage bitcoin addresses in a trustless manner, allowing people to trade bitcoin for litecoin through an ethereum smart contract, without anyone being able to stop you, no KYC, no limits on your "account", nothing. Although most people are more excited about "smart contracts", allowing a traditional ethereum contract to check things about the real world, without points of failure like a companies proprietary oracle. For example right now you've got oraclize.it, if it dies, as it's a regular web server, a bunch of contracts become useless, so it's completely out of line from blockchain tech. Chainlink is supposed to be a separate blockchain on its own that houses oracles. I guess there's room for goofier examples, with how package tracking today works, you could make a contract that only pays the vendor when you've received your package. This can expand to shipments beyond stuff from ebay, companies like walmart already use blockchain (Hyperledger specifically) to secure shipments. Yeah it could easily be done today with some 3rd party web server holding the cash, but that's not really in the spirit of trustless decentralization now is it?
This is all theory, Chainlink isn't done yet, and if it's on the ethereum network (technically Chainlink can work with any blockchain there's just an issue of writing the endpoints which isn't rocket science) it's gonna work like dogsoykaf as any ICO or new cryptokitties clone crashes the network with no survivors. Perhaps after POS & Sharding it won't be that bad.
Also following things like when smartcontracts.com was registered, it's very hard to argue that chainlink wasn't the first, even if their ICO perhaps wasn't. This isn't saying you should buy CL, I hold some as suicide insurance because of memes. Not even joking.
Disclaimer: I still own some ChainLink tokens.