This is the reason I am now on an iPhone after being on Android since ~2009. But this could also apply to Samsung too. There were two watches I was considering - Samsung's and Apple's (for health monitoring reasons, I have a family history of heart problems, and am already nearly 10 years older than my dad was when he died). I would either have to buy a Samsung phone or an iPhone to get the functionality I wanted, and TBH I really don't like Samsung's take on Android (I've been either Cyanogenmod or Motorola for over a decade), so an iPhone it was. But I would have preferred to get an Apple Watch and have that work fully with my Android phone, but that's not even a starter, let alone the limited-functionality you would get with a Samsung watch with another Android phone.

I'm happy with the watch, and I now like a lot about the iPhone. But it was 4x the price of my previous phone.