I keep waiting for Slack to realize that they're a big enough company now that they can afford to make native apps that look and work better than the Electron version. I'd much rather have a real native app than a webpage inside some minimal window chrome. Different strokes for different folks I guess.
The Slack client looks nice but it's incredible how inefficient it is (presumably due to being a web app in an Electron wrapper). I used it recently on a low powered laptop and keystrokes sometimes took 100-300 msec to appear on screen. No other text entry application on that computer had that problem.
It's still going to be a bit of a problem, as you have the Unix terminals (bash, zsh, fish, among others), and then you have the Windows terminals (cmd.exe and PowerShell).
Or, option C: You use Electron, like Slack.