I was in another country when there was a power outage at home. My internet went down, the server restart but couldn't reconnect anymore because the optical network router also had some problems after the power outage. I could ask my folks to restart, and turn on off things but nothing more than that. So I couldn't reach my Nextcloud instance and other stuff. Maybe an uninterruptible power supply could have helped but the more I was thinking about it after just didn't really worth the hassle anymore. Add a UPS okay. But why not add a dual WAN failover router for extra security if the internet goes down again? etc. It's a bottomless pit (like most hobbies tbh)
Also (and that's a me problem maybe) I was using Tailscale but I'm more "paranoid" about it nowadays. Single point of failure service, US-only SSO login (MS, Github, Apple, Google), what if my Apple account gets locked if I redeem a gift card and I can't use Tailscale anymore? I still believe in self hosting but probably I want something even more "self" to the extremes.
I have 7 computers on my self-hosted network and not all of them are on-prem. With a bit of careful planning, you can essentially create a system that will stay up regardless of local fluctuations etc. But it is a demanding hobby and if you don't enjoy the IT stuff, you'll probably have a pretty bad time doing it. For most normal consumers, self-hosting is not really an option and the isn't worth the cost of switching over. I justify it because it helps me understand how things work and tangentially helps me get better my professional skills as well.