Yup. Those are words that the person you're responding to said. Quoting them here, though, doesn't make your off-base tangent about Electron any more appropriate as a response to a question about Chrome displaying a screenshot in a browser-controlled popup.
The installability of said Web apps was a thing prior to Chrome's announcement of the introduction of the "screenshots" property to the installation manifest. You are not answering the question that the person you responded to actually asked.
You're on a Web site. It has an "Install" button that you can click. Following the change announced in this post, the popup that overlays the page content can now contain a screenshot of the site operator's choosing when Chrome prompts you to confirm installation—a screenshot that could just as easily appear on the page—i.e. the one that you are already on and that contains the install button you just clicked. The question, then, is: ignoring all the puffery and filler the blog post, what _actual_ problem does this (the "screenshots" property—and not a PWA in general) actually solve?
(Alternatively, you can say something like how you were so excited when it seemed like there was an opportunity to post a vaguely cynical and nearly zero-effort quip related to installable Web apps vs Electron that you came in firing from the hip which resulted in what, as it turns out, was a response to a different question that nobody here was actually asking. It's as simple as saying, "Oops. I was mixed up, and I don't have such a big ego that I can't admit this nor one that requires me to pretend that this is what I meant by my original comment in this thread all along.")
"Why do I need a screenshot of the "app" (i.e. webpage) I am already using?"