Originally Posted by
z28lt1
Seems like only certain features require the phone to be on.
From inc.com
https://www.inc.com/associated-press...n-battery.html
"Phone calls and iMessage chats work on the watch even if your phone is off, as do turn-by-turn maps and queries to the Siri voice assistant. For texts, the phone needs to be on -- somewhere. With the phone on, you can perform a variety of other tasks, including checking weather apps, Yelp recommendations and notifications that go to the phone.
Coming soon: the ability to stream Apple Music, even with the phone off. Unfortunately, this doesn't apply to rival music services or Apple's podcast app."
The reason for the SMS not working without the phone being on is to do with the way SMS works I believe. If you have multiple devices on one number then only one (the primary sim) can receive the SMS. Therefore the Phone is the primary sim and the Watch the secondary which is why the phone needs to be on to get texts. I may be totally wrong on that but that's what I understand.