Earlier quoted context omitted.
do you really though
If it makes for easier programming, yes. Writing Slack as a native app would be a massive pain. Especially due to all the web-like features it has, the fact that it's one codebase (mainly) for desktop and web. They also have to support Windows, Linux, Mac and mobile. Not an easy task
Windows and Linux are another beast, and Telegram’s solution is to use Qt for those platforms. Again, slack like capabilities with no webviews.
The difficulty of native dev is not as high as it’s often represented.