It’s the only service I don’t self-hosted, although I do backup my email on my home server. Email protocols don’t tolerate downtime, if your server is temporarily unreachable you won’t get messages and people will probably assume the email address/domain isn’t even valid.
If your server goes down you’ll miss incoming emails, and IMO residential ISP and power service isn’t reliable enough for your main email address. If mail can’t get delivered people get the impression you gave them a fake email address, which can be more than embarrassing.