I'd argue that they all have their place. Anything of great length that's related to something product wise that has impact should be discussed in an epic or ticket that links the main point back.

As anyone who's followed a giant email chain, I think that slack is at-least a little bit easier to follow. Albeit I'm working in a company that is just now trying to start to emphasize stories/tickets/chat over email for everything, with tons of pushback.

Gone are the days of email everything, tons of people are CC'd, email chains are 30-50 responses in. It's absolutely unmanageable. Oh and if you drop chat, let's start logging alerts to email, or bugs to email. It's useless.

Personally I'll use chat for anything relatively quick or unimportant in the grand scheme of things. I'll use email for when it's not something that requires a response right away but generally is also unimportant to the company projects and doesn't involve a ton of collaboration. Anything bigger than that goes in a system that's suitable for tracking projects or complicated topics.

I don't think there's a one size fits all solution for communication.