Earlier quoted context omitted.
A browser is like a buggy mini-operating system that hogs resources, tries to replace native applications like PDF readers, word processors, and email clients, and uses JavaScript as its system language. Client applications circumvent the hell of modern web browsers. The benefit is not needing to use a web browser.
Wish there was some kind of a "Electron kitchen" where you could easily make your own app stating which website you want to use in this isolated way, without having to learn about Electron.
I use this for reading my gmail. I use the --user-data-dir flag to prevent the "app" from interfering with my other browsers.