I stream the video over adb myself, to make sure I don't drain the battery too much and to keep everything wired.
If you only join from your phone, you can't really see other participants (unless you use your front cam, and in that case your screen is obviously still very small) and you won't be able to screen share.
If you join on both, you will be in the meeting twice (which can look weird to other people). In my case, I want to use a dedicated microphone, not my phone's microphone that might be blocked by the arm that is holding it in place. That results in a weird AV delay since the audio is coming from a different user in the call (and it means your video is not highlighted when you speak).
In short - my current setup hides the implementation details and makes it all work transparently without bothering people I'm in a call with.