The benefit for Apple is how it could work with iOS/Macs and Apple services. If it is able to play Apple Music and also send that stream to any or all Airplay receivers I have in the house, it would be worth paying more for their product. Siri can already handle most of the things I use the Echo for. It can turn on and off lights, it can set alarms, and reminders, and tell me sports scores and the weather. It could also have the advantage of handing off to the iPhone. In other words, I could ask Siri for the closest Tex-Mex restaurant and it could send directions to the phone. It could just work more seamlessly together rather than being a stand alone device than never leaves the house.
It could be possible to tell it to pull up your dog photos from your library and Airplay them on the AppleTV or tell it to show the video you shot this morning on the TV. This is the same way Casting is helping the Google Home. My main issue with Google, even though I am subscribe to YouTube Red, is that I don't want them tracking everything I say. I just think Apple is less creepy in a lot of ways. I don't mind Amazon, but I believe a lot of people will pay extra for the level of security Apple will most likely put on this device in addition to having another way to take advantage of the Apple ecosystem.
Right now, we really don't know what Apple will bring to the table, but the Apple Watch shows you just how many people will buy devices that plug into the Apple Ecosystem and give them an extra level of convenience. If Apple does this right, I have no doubt it will have some level of success. If it is like other Apple products, it could make the most revenues in the category while still not having the largest market share. Time will tell.