For me this depends on the context:

1. On the first message of a conversation I prefer a wall of text, because that lets me read all of the details really quickly.

2. If the conversation is likely to be short I prefer the one message after another since my attention is already on the chat, and I might as well be reading what they're typing rather than watching the "x is typing..." indicator.

3. If the conversation is going to be long I much prefer a call, I don't have the time to wait for someone to type all day. Context switches are expensive so I don't like reading occasional long messages while I'm trying to work.

Why would you need a follow up question more for a bunch of lines of text vs a block of text? We're talking about putting a bunch of new lines (i.e sending many messages) vs sending just one large one. They can contain the exact same information.

For an initial message (no hello) this is great. But when we are already chatting and my attention is on the window, I prefer shorter messages.

That's where email/mailing lists shine.