Maybe you can download an app on the newer Apple TV's to replicate it, but I think the 3 was the last version to have the radio feature. I keep one hooked up to the TV in our family room just for that purpose. That was a really easy way to find music (I guess if you subscibe to Apple Music or Pandora or something, that wouldn't be a huge selling point).
The Apple TV 3 also has the Amazon Prime TV app, which I believe the 2's didn't, so that's also a nice feature. The device is old U& somewhat slow, but if you already have it, it's still a pretty great little device, and well worth hanging on to in my opinion. I probably wouldn't go out & buy a new one today, but I think it still serves a purpose if you already have one.