It actually does add quite a bit of functionality for Apple product users. . . and it is planned to be the hub of the connected home for Apple products in the future. As such, the price is quite reasonable. Those other devices are essentially just streaming video devices with no further function. For the major differences between the Roku 3 and the new Apple TV, I refer you to my reply 31 in this thread.
There have been so many anti-Apple hate Brigade members throwing spit wads of misinformation and trying to obfuscate what these new Apple products can actually do by comparing them to older, already on the market competition that do far less, instead of actually even looking at what Apple has publicly stated their new products ARE capable of doing. I point out the repeated efforts to denigrate Apple's new Apple Pencil, by continually calling it a stylus and ignoring what it actually can do, despite being told repeatedly the actual facts, which they repeatedly ignore.
Does the Roku have 64GB or 128GB of native fast storage on it? No? I thought not.
No, Roku does not. Curious to know what Apple plans on using that storage for (movies? Music?)
How about mirroring your computer's, phone's or tablet's screen on your big screen TV wirelessly? No, not possible with a Roku.
Roku = no. Google Stick = Yes. Granted, it's pretty crappy functionality.
Hand off playing a game you were playing on your phone right onto your big screen TV without interruption? Uh, no. Not possible with Roku.
That's also not the purpose of the Roku, so I'm not sure that's a fair comparison. How many people do you think would actually use that functionality? And then, how long until the novelty of it wears off?
Instantly stream your home videos or photos to your TV from your phone where you took them or from your computer where you store them. Uh, no, not from your Roku. You have to sneaker-net them over there on a flash-drive. How antique.
Using Roku with PlayOn enables this functionality quite nicely but you're right: it's not "native" to the Roku device.
How about asking a question about the movie you are watching WHILE watching it and get an answer shown on screen while you are watching? Uh, no, not on Roku.
Again, not a feature of Roku and at a $49 price point I'm not even sure that'd be a reasonable expectation
How about asking "What did that guy just say?" and having Apple TV back up 15 seconds, turn on closed captioning temporarily and do an instant replay the scene in question so you can not only listen, but SEE what that guy said! Not on Roku.
Actually, yes you can do this on Roku. You may not like how it works, but it does it.
How about orally telling the system to backup five minutes and play from that point. Nope, not on Roku. . . doesn't do that, but Apple TV will.
Sounds like a neat feature, although I personally have issues talking to my computer/any device to tell it what to do or what I want, but that's just me.
I think what you've done here is demonstrated one of my earlier points on this thread in which I said Apple knows how to develop and market features to their user base, even when that user base may not have even thought they "needed" that functionality in the first place.
That is one of Apple's strongest merits: cultivating their user base.