Earlier quoted context omitted.
> Not a fan of these types of services myself What do you mean by "these types of services"?
CircleCI is a CI/CD solution (ala SaaS) that you don't host yourself. Many (myself included) prefer to host mission-critical services ourselves to avoid untimely downtime.
E.g. I've worked in a business who self-host their Gitlab instance, there was a non-negligible amount of work for backups/upgrades on top of troubleshooting performance issues once in a while, amongst other things in the same vein.