This is a detailed topic. Yes in essence they are bridging platforms but there are also deltas
First the obvious one on premise vs cloud Further more CMS legacy is a video first and foremost platform. Sure it does content share but no whiteboard and doesn’t have all the centers like event and training and support
Scalability is higher with cloud obviously
CMS traditionally has support for dual homing with MS platforms that Webex doesn’t have. Google dual homing for more details
CMS uses clients like web rtc with chrome and FF but on iOS and edge and IE it nerds thick client which adds another edge box
Webex now with video mesh node can keep traffic on premise optimally to give you benefits like an on premise cms server
CMS can provide 1080 p 30 FPS on video and content vs Webex is 720p on video and content and further more the content is only 5 FPS. You can get 1080 p with Webex but only on premise end points can benefit from that on the node but even in that design content is lower frame rate
Recording in the cloud is built in vs cms that needs a recorder server plus licensing, Same with streaming
Management of CMS is rudimentary via CMM and further more configuring and setting up is using post man which can be CLI heavy and demanding base on your skill level vs Webex
From a strict future direction Cisco lead offer is Webex as stuff moves to cloud and CMS is secondary
