I think some comments are missing the points a little bit. It's not just about scale and I think not at all about not needing new addons to the project not wanting to decipher your bash wizardry. Deciphering Jenkins pipeline scripts or Ruby playbooks for Chef is no easier. In fact, fully figuring out what a Chef recipe will do without running it can be quite inscrutable, way more than figuring out a shell script.
But Jenkins and Chef give you servers. The pipelines or recipes are in a central location with access control that can tie into the same sso or ldap controlling access to everything else in your IT infrastructure. They can run automatically without having to install separate cron jobs on every server you own. Your deployment scripts are probably running from your laptop, which is accessible only to you, not always connected to a network, probably not accessible remotely to anyone, may or may not have any of its own backups, might be unmanaged and impossible for a third party to know you're running it securely and it doesn't have malware.
Organizations are trying to avoid having Dennis Nedry control all of the core infrastructure they rely on.
Sure, as an individual consumer, I might have questioned the utility of something like dropbox, and as it stands, I have never personally used it. But I don't question the utility of distributed filesystems existing when you could just have cron run periodic rsyncs between the root filesystems of some arbitrary number of servers. Yeah, ultimately Chef and Jenkins are just doing what your shell scripts are doing. But Chef and Jenkins are real software. They're well-tested, have a formal development and release process that involves peer review, they're used by thousands of other customers, they come with support contracts and SLAs. Your shell scripts don't have any of that.
But Jenkins and Chef give you servers. The pipelines or recipes are in a central location with access control that can tie into the same sso or ldap controlling access to everything else in your IT infrastructure. They can run automatically without having to install separate cron jobs on every server you own. Your deployment scripts are probably running from your laptop, which is accessible only to you, not always connected to a network, probably not accessible remotely to anyone, may or may not have any of its own backups, might be unmanaged and impossible for a third party to know you're running it securely and it doesn't have malware.
Organizations are trying to avoid having Dennis Nedry control all of the core infrastructure they rely on.
Sure, as an individual consumer, I might have questioned the utility of something like dropbox, and as it stands, I have never personally used it. But I don't question the utility of distributed filesystems existing when you could just have cron run periodic rsyncs between the root filesystems of some arbitrary number of servers. Yeah, ultimately Chef and Jenkins are just doing what your shell scripts are doing. But Chef and Jenkins are real software. They're well-tested, have a formal development and release process that involves peer review, they're used by thousands of other customers, they come with support contracts and SLAs. Your shell scripts don't have any of that.