So true. I had to stop loading Slack at startup because it was using 400MB of memory and running eight threads. As the article says, come on, "It's just a text chat app." For Electron to be viable we need a "Chrome Core" library that just has a JavaScript engine and some OS glue.
There's no reason UIs should be laggy in 2016 on the very highest-spec Lenovo Thinkpad mobile workstation, but that's the sad reality of anything written in Electron JS (along with Electron's absolutely zero 4K Hi-DPI support on Linux, so I have to squint to read the microscopic text on Slack, Upwork, Discord, Messenger for Desktop, Whatsie, Skype for Linux Alpha, Atom, sometimes VSCode ...).
What benefits does running the "native" Slack app give over accessing the site in your (presumably already-running) browser?
A separate icon in the Dock, I suppose.
Theoretically, OS and hardware access outside the sandbox most browsers are confined to.
Toggl for example can log time per window title when it's app is running on desktop.