Why should I not use Electron? There are many reasons the Electron library is terrible. Notice the wording I use, I say: it emulates a browser. What I mean is, it creates a run time environment with Chromium as the backend. A reasonably modified version of Chromium is what Electron uses. To say this is a bad idea is an understatement. Not only is this a slower method of running a browser, emulating. There are many ways to do emulation, but that isn't required to explain. Emulation is a slow process with running everything on the front-end. While emulation isn't the most delayed, it can be as sluggish to run as containerized systems like Snap.
The main three issues behind Electron being terrible are that it uses emulation or emulation-like systems. It doesn't have a custom HTML/CSS engine. It borrows from Chromium, a browser not too keen on speed. Removing any one of these issues will make others either mute or disappear. Replacing Chromium will help speed enough where we can ignore the emulation, and the custom HTML/CSS engine can be put off. Using a custom HTML/CSS engine removes the issues with speed in emulation and the Chromium problem. Removing their emulation, and using the code from Chromium itself, will make the speeds of Chromium not important enough for the short term to get a new engine or make a custom-built engine.
Electron has issues, but as a whole, the project is usable and well documented enough to say it is still a decent project for web applications. These are my complaints and from my technological standing of how Electron works.