Keynote Live was an early approach to distributed presentations that relied on iCloud to send near-time updates to the viewers.
The main disadvantages were latency and that it ran in its own application space and therefore didn't integrate well with video conferencing apps - it was hard for many people, for example, to be in a zoom meeting in one window while the presentation ran in a separate application window (especially on devices like iPads where Zoom takes over the entire screen).
More recently Apple (and the various video conferencing apps) worked towards direct integration, where the video conference can show a single video stream of the presentation, capturing directly from Keynote and showing in the video conferencing app, even overlaying the presenter's camera view over the slides.
This was also closer to real-time and everyone saw the presentation at the same time, avoiding the latency involved with the Keynote Live model.
So in most cases, video conferencing apps offer a better experience than Keynote Live did, so consider using that instead.