In your opinion. My own experience with Confluence is that it's essentially write-only memory. So much documentation that goes in to my companies Confluence becomes outdated _very_ quickly, but is rarely, if ever, actually kept up-to-date. This leads to a system whereby people appear to be generating a lot of functional utility for our company and our documentation purposes but it's little more than noise when you are actually trying to find that utility.
I'll absolutely grant you that it's better than internal networks. No arguments there. I think that I do prefer e-mail, though, because, at least with Office 365 and Outlook, the search function is actually useful compared to my experiences with Confluence.
I do (obviously!) hate JIRA, but I just don't like Confluence. It feels like where documentation goes to die, the search function is useless, and I find myself constantly hunting for tiny little buttons and links to attachments.
I hate Confluence and am absolutely stealing that phrase!