Why do all the actors wear apple watches instead of Samsung watches?

because apple is the cool thing to wear

They got them for free. Actors are constantly being giving free everything as PR.

Trend.

Because most actors have apple products. It's a very popular brand.

All which actors?

You've got a pretty keen eye to be able to tell what wristwatch all actors wear, even through their shirt cuffs and when their hands aren't even on camera, apparently. That's pretty amazing. But if more actors do wear Apple's smartwatch, then I'd say it's because Samsung's s so inferior to Apple's. Apple's costs more, but celebrity actors, which I presume are the actors you're referring to, have enough money that they're unlikely to fret over a couple hundred dollars and so likely to go with the better watch over the cheaper watch.