One thing I noticed today is that now when I consider any app for purchase, I check for wether it has support for the watch and wether this support makes sense (e.g. today I was looking for a pomodoro timer app).
None of what I write above I would have guessed from the product description and the advertisements. Whether it is useful to you or not will depend on the apps that exist and your lifestyle. It's hard to predict and expensive to test. YMMV