I'm not sure when, but at some point they switched so that you don't pick a location for chains. E.g. you just order from "Wendy's" and Uber picks which location it comes from. That's why you don't see a dozen McDonald's in the list anymore.
It does tell you how far the location they're using is if you keep an eye on that. I've also been bitten because I forgot to check and Uber decided to try to deliver from a Wendy's 15 miles away instead of the one a quarter mile away.
If I just click the fast-food button, it only shows 1 McDonald's. But it's because it's a sponsored listing and I can still see the address of the store when I tap on it. It says it's 0.9 miles away.
It does tell you how far the location they're using is if you keep an eye on that. I've also been bitten because I forgot to check and Uber decided to try to deliver from a Wendy's 15 miles away instead of the one a quarter mile away.