Unless you like carrying a smartphone in your hands all the time in crowded places, or like leaving your smartphone on the table where it can get lost or stolen, the smart watch is better. Nothing beats a watch for quickly checking something. Constantly fishing a phone out of your pocket, unlocking it, checking stuff and putting the phone back in your pocket can become extremely tedious quickly.
Can't say I've ever left mine anywhere. And I have no problem getting it out of my pockets. Meanwhile a watch is fucking uncomfortable to wear, and tends to break within a few months as you accidently bang it on things. I cried tears of joy the day I realized my new cell phone meant I'd never have to wear a watch again. I think taking it out of your pockets is a problem only about 1% of the people in the world have, everyone else seems to prefer the phone.