I'm thinking of getting an apple watch with the cell phone. It's not usable for web surfing and other addictions, but it still has phone, messages, and maps, which are what I really can't do without.
I looked into this, more as a curiosity. The thing that killed it for me is the battery life. Unless your usage is already very low, I expect you'd end up charging it more than once a day which for me was prohibitive.
You don't need the iPhone on your person when you have the cellular version of the watch, but you'd still need to own one.