I agree that these apps rarely crash, in the strict sense of the word. I don't think I've ever seen Slack get into a state where it's misbehaved to the point where the broader operating system has seen fit to kill the process. However, I have seen Slack get into weird states (like not updating read/unread status of messages, waiting forever for content to load, not showing notifications, etc) where the only way to fix the application was to quit it and restart.

So no, Slack (and other Electron apps) don't crash. But maybe they should. A hard crash (and automatic restart) is often better than the slow creeping insanity that seems to afflict Electron apps when their internal state gets out of sync with itself.