One reason I have found real-time communication ineffective is that it favors the narcissists and egoists in the conversation who are comfortable talking over everyone else.
Guess what happens in this situation – Bob spends 40 minutes talking out of the hour's meeting about how his way is right, interrupts everyone, and by the end of the hour meeting the boss is saying “Well, why don't we do a proof of concept with Bob's suggestion” simply because everyone is bored and hungry. Meanwhile, Jane had a novel and imaginative idea that went completely ignored because Bob kept cutting her off saying why it wouldn't work early on when she was trying to explain the concept.
Oh, and did I say that this interruption and talking for a long time seems to get ten time worse over video calls for some reason – perhaps because Bob finds it easier to pontificate while in his pajamas compared to having to stand up and talk in front of his peers in the office.
Yeah, I know the standard retort for this is "your meeting must have an agenda" et cetera. Guess what, look at the last 5 meetings on your calendar and tell me truthfully how many of them have a real agenda (mindlessly repeating the title as the description doesn't count). People don't want to do it, because, guess what, it adds an element of asynchronous communication when you have to think of the agenda ahead of time.
So, I have found that just going the whole way and just having the entire communication asynchronously is often better at ensuring more equitable participation.