"I always hated "15 minutes of real-time conversation", not because of being an introvert or anything, but because it's fuzzy, nobody remembers what it was exactly said, and usually ends up with people wasting each others time (like Diltert-style meetings)."

I'd say the solution is to attack those problems directly.

There are some things that just work poorly asynchronously. I find heavy-duty explanations of something, where you need the highly-interactive back-and-forth is necessary, and honestly, even just trying to type something is wasting minutes vs. saying it, is a common use case for me. Getting 4 half-distracted managers who are lobbing emails at each other into a quick conference to resolve the matter is sometimes a really good idea, too, because the "lobbing emails at each other" is a political minefield. A lot of potential for hurt feelings and miscommunication that can be avoided just getting everyone in live voice chat, with their full attention, for even just 5 minutes sometimes.