A new capability of the Apple TV is what Apple is calling "Live Tune-in", the ability to simply tell Siri, "Play [channel name]" and proceed immediately to the video stream. The notion is that it will speed up navigation, bypassing the pesky remote (that you designed, Apple) and crummy app interfaces (they're still the future!). In practice, though, I haven't found it to speed things up at all.
First, tuning in live only makes sense when you know what you want to watch is on right now. This makes sense for live events, like news and sports. Yet many of the channels available for Live Tune-in broadcast pre-recorded programming. Apple TV users probably aren't in the demographic who think "gee, I'll see what's on NBC right now." They want recorded programming on-demand and live programming on-command. That's what Live Tune-in promises, but doesn't yet deliver.
As an example, the European soccer championships are going on this month. They're broadcast in the US by ESPN, whose main channels (ESPN, ESPN2, ESPNU, and ESPNews) are Live Tune-in capable. For the final matchday in each group, two matches are played at once, possibly deciding the qualification fate of all four teams. Those games are broadcast on ESPN and ESPN2 — but I have no idea which one is carrying which. Live Tune-in requires a channel name; I can't say "Siri, show me Italy vs. Ireland." I could try "Siri, watch ESPN," and follow it up with ESPN2 if I'm wrong, but at that point I might as well have gone to the app, where I could read the program names and not have to guess and check. Another recent example is the NBA finals, which were broadcast on ABC and simulcast on ESPN3. As the bartender at the sports bar I frequented during grad school told many puzzled cutomers asking him to switch a TV for them, "ESPN3 isn't a channel, it's a website," and that means no Live Tune-in — even to a record-setting live broadcast.
I can't help but think this is a problem related to the SiriKit limitations I discussed yesterday. Live Tune-in isn't a tvOS feature so much as a Siri feature. (Eddy Cue touted it as being new at WWDC, but it's been available since April; the news is that, intriguingly, it will be coming to the iPad in iOS 10.) Once again, the trouble is hooking up Siri to a catalog of ever-changing data. A static list of channels is simple; it's just a lookup table between names and deep links. A programming guide seems simple too. Every cable box on the planet has one; you just can't command them by voice. Live Tune-in is a step towards a TV voice interface so simple that "it just works", but for now it only works if you know exactly where to go.