Apple

One thing that hasn't been mentioned is screen mirroring. You can do it from your phone or computer, it comes in handy. Photos, documents, whatever else. Nice to be able to quickly make things huge.

Using your iPhone as a remote enables extra laziness.

Using your Apple Watch as a remote enables extra extra laziness.

Asking Siri "what did he say?" rewinds and temporarily turns on subtitles. Clever feature.

Integrating shortcuts is next level.

Using your iPhone as a remote keyboard is the height of human achievement. Saves so much time and frustration.

This question is asked a lot on here and answered a lot in blog posts. Next time try searching for previous threads, or maybe get more specific on what you're looking for. I get where you're coming from, though. It's exciting and sometimes we don't know what we don't know.