Earlier quoted context omitted.
It's better because X might take a while to write correctly, and you might want some assurance that you have the other person's full attention first before you even send that message. It's a commitment mechanism of sorts.
This doesn’t make sense to me. What does it matter if you have their attention first? It’s asynchronous communication. I find it so damn rude to demand my attention first before you begin typing out a long message. Like do you want me to watch the chat bubble animation while you type or something?
In addition, seeing the chat bubbles appear moments after you finish your round is a good sign the other person isn't multitasking and letting their own attention get fractured.
I never found it rude to begin with, just not using the medium to its strengths. But this has me realizing maybe it's a deliberate way to eschew those strengths, for some purpose or another.