If the conversation is at the point where you are replying to replies, and you’ve sent me three rebuttals with each of them asking for clarification or verification from me, I’m now sending 3-6 replies back, which may require you to send 12 or more.
You are right that the amount of comments would grow rather quickly (exponentially, I think), but the threads, themselves, should be easier to follow — there wouldn't be multiple conversations happening within each comment.
I’d lose track of who said what and would end up referencing something from a conversation with someone else.
How come? The comments are all visually tied together in the thread hierarchy (well, assuming that one isn't reading Lemmy content from Mastodon, or with the Chat mode in the Lemmy UI)