Thanks! Yes, Let's Encrypt does email you, and they provide extensive documentation for automatic renewals as you say. But even with that, I've had some WordPress instances go dark a few times because of some hard to debug problems with the cron job while running inside a Docker instance. Also, it's nice having everything in the same dashboard if you manage several sites. Peace of mind.
Regarding the signup email, thanks for the heads-up. I just fixed the issue and if you want to give it another try, you can just register once more.
Much appreciated!