"Controlling the ecosystem" and "integration" and such are just wishful-thinking rationalizations. Chrome and Electron will use however much RAM they use; Apple can't magically reduce it. If you need 32GB you need 32GB.
My guess is that it's an ARM build of Electron - unless they've been working to bring the iOS version over? That would be a huge win.
Even if this is Electron, I suspect this still great news for anyone that needs Slack. The Rosetta 2 performance of Electron would likely be a dog and Slack is a very high profile app with a lot of visibility.
Yeah, that’s partly true. Applications that allocate 1000GB will need to get what they ask for. No getting around bad applications. The benefits are more in terms of lower level systems communicating by sharing memory instead of sharing memory by communicating, which is always faster and needs less memory, but needs full trust and integration.