Would be great to have a small SMTP client in the Node software, so each Node operator can connect to a SMTP server (own server, or a publicly available like Google) and so enable the Node to send notifications messages, like for example:
You can use other monitoring systems, like zabbix for this. I do not think that doing self-monitoring would be that useful and worth the effort.
After all, if the node goes offline for some reason (crash or just a problem with your internet connection), it won’t be able to send you the email.
I would it like if they added some more information to the API (success, fail counts, service time etc), but IMO doing a complete self-monitoring would be not worth it.