When LetsEncrypt came out, I wrote a service (free) that monitors LetsEncrypt certs externally and sends alerts when they are close to expiring. It can be used as a backup to the automatic emails that are sent:
1. Why not integrate and let user monitor all their SSL certs for a domain in a single shot? Like retrieve all certs for a domain (similar to https://crt.sh identity like search result)
2. When registered, I did not receive an email confirmation/validation. So I am not sure if I will get an email before my certs are up for renewal.