It's a valid comparison because of all of your points. The question here is: why use Electron as a stack at all. The general arguments are to do with building

It's a valid comparison because of all of your points. The question here is: why use Electron as a stack at all. The general arguments are to do with building modern, aesthetic, easy-to-use cross-platform apps with less dev resources. Slack as a company are not dev-resource-constrained, so this makes Krita an exemplary counter-example to anyone who ever defended Electron for these reasons.