This is a big reason why asynchronous communication works better for me. I can't begin to count the number of problems I've solved in the process of writing an email asking for help. And many more times where the question I was intended to ask changed to a completely different, and more useful question. The process of collecting the information I have, ended up pointing to holes in my thought processes and led to the solution.

If I had gone straight to Slack I would have wasted other people's time, and cheated myself out of thinking through the problem myself.

Kind of but writing has the added benefit of being easily inspectable after fact. Speaking out loud will identify some weak logical points, but writing will catch even more.