Most complaints about Electron that I see are about memory usage. If you’re running on an old laptop with little RAM, running 3+ Electron apps can start to slow your entire system down.

There’s also a breed of users who are extremely sensitive to the “native feel” of a desktop app. For them, it’s a jarring experience to downgrade to something that is less snappy, but they expect a certain standard of snappiness.

Because every Electron app is basically its own Web browser with all of the app's code being JavaScript, rather than the app just being native code. Try running Chrome, Edge, and Safari all at the same time and look what that does to your computer's resource usage. Electron apps basically do the exact same thing.