What exactly is Let's Encrypt email used for?

[Falco]

LETSENCRYPT_ACCOUNT_EMAIL no longer needed

As of June 4, Let’s Encrypt stopped sending email notifications about failing renewals, which was the only reason to have that ENV variable set. I just ran discourse-setup-ruby and didn’t get a email address for LETSENCRYPT_ACCOUNT_EMAIL and now Discourse won’t work because the clever logic refuses to request a certification if there’s no email address. It’s been almost a year since including an email address in that variable did anything. So this if needs to be deleted: