It all depends on how much time do you spend playing on your XB1. If you only use it to play some Microsoft games, then it probably won't worth it. But if it is the machine where you play lots of third-party games and you use B/C a lot as well as you have a 4K TV, then I think you should go for it.It will still be supported for at least 4 years even sometime after next-gen starts.
I play most of my third party stuff on Playstation right now, because I have a pro. I also have a friend that plays tons of games, so I borrow games from him for free. Making an Xbox my main third party machine will also mean that I have to buy more games then I otherwise would. However, the single game that I played the most, by a very large margin, is Destiny 2. I play Destiny on Xbox because I like the Xbox controller more than the dualshock 4 shooters.
I do have a 4K, HDR TV.
I think I'm going to float it past the wife and see how much resistance I get. If she's going to use it as an excuse to spend 500 bucks on other stupid crap, I think I'll skip it. If she doesn't seem to care, maybe I'll take the plunge.