Apple Watch Cellular can work autonomously, without the "host" Iphone.
Webex Meetings is supported on it, but unfortunately Webex Messenger is not.
From technical point of view it doesn't look a big achievement to support Webex Messenger.
The situation is that I do watersports (kite-surfing), and I want to see my messages on my Apple Watch. I don't want to take my phone (even in a waterproof bag), because I cannot place it anywhere.