I think your criticisms were pretty fair of the earliest releases of the Let's Encrypt client, but they seem to be less accurate now. We see the client (aka Certbot) being used successfully by many hundreds of thousands of site operators. In terms of full automation, the Apache plugin has gone from "experimental" to "works for most people automatically". We'll be working on delivering similar features for Nginx next.
But if lego works for you; that's great!