I hate to defend Slack as it's far from snappy, but comparing it to a console app seems hardly fair.
I wonder how much of it's slowness is due to network requests? I could make the argument that git is slow because when I clone a large repository it takes a while.
The git equivalent would be if you had to wait for git to do a fetch/pull every time you ran "ls" on a git-controlled folder. It would be insane, and no one would use git (or any other version control).
Especally when we have excellent examples like VS Code, which is cheerfully giving neovim and emacs a run for their money and displacing longtime contenders like sublime, because it's genuinely quite good and plenty fast enough for most folks.
However, I agree Slack's got a lot of issues that are just bad implementation choices.
But the reality is is that Slack is an application made by a real company by real people/developers who all faced real constraints. Go build Slack for yourself, through the same history they have, and lets see what we come out with.
The equivalent with git would be having each directory be a submodule and someone is rewriting the history out from under you every few seconds.
For technical people it’s easy to assume we understand the problem especially when we see what looks like a questionable design choice but when we do this to applications we don’t have experience with it only hurts us collectively.
* DCC is still unreliable.
* There is no audio connection option, which is quite popular in 2018.
* Channel history management is ad hoc
* Authentication is done in band, in plain text.
* "secured" channels rely on this bad authentication, and if they don't (perhaps electing to manage it themselves) network flaws can completely steal your channel.
* IRC isn't even particularly open source, many servers and networks have private patches that are not shared publicly.
IRC isn't better than slack. I agree with you that it's confusing why people suggest that it ought to be.
Also, most IRC networks are controlled by entities even more inscrutable than Slack's executive team and board. I can go look up who runs slack, I cannot actually find good details on who runs any given IRC network. I have no idea what I'm dealing with or how they're using my data. I have no legal recourse if I do discover bad behavior, and I'm forced by the ossified protocol to keep using their insecure authentication mechanisms which make abuse trivial.
Ah, the good old days of the Internet. You make me so nostalgic.
I've used slack on mobile and I find it worse than the desktop version.
It starts slightly faster (10 seconds vs. almost 20) but navigating through channels is bad (and slower) and threads are completely unusable. It also runs my device hot like nothing else.
The faster startup speed isn't a big victory for me because it's still a factor of 10 away from what I would consider acceptable.
The "best" interface for slack, IMHO, is the web version, provided that you are already using Chrome.