I think somehow the idea that you should keep your main branch buildable/shippable at all times (a good thing imo) evolved into, since it is shippable, it should be shipped automatically (which is, in my opinion, really suspect)

I'm in the same boat though, I don't get the point of CD for most applications other than to prove that you can do it (but other than impressing other engineers with your teams apparent discipline: who cares?)

Minimal code delta means the isolation of any bugs is much easier than if you have to read through six months of patches.

Ability to get user or system feedback on code today, rather than in three months, is often quite helpful. That is, if your company depends on listening to customers or studying customer behavior. (I know of no company that isn't, though, except monopolies like Comcast.)

> Minimal code delta means the isolation of any bugs is much easier than if you have to read through six months of patches.

Sure... which is why your QA department should test things early. (You're not making your users into QA... are you?)

> Ability to get user or system feedback on code today, rather than in three months, is often quite helpful.

Users-as-beta-testers can work in some contexts, but there's a lot of of fields where doing that is a very bad thing. Experimenting on your users is, at best, a pretty nuanced business decision. And: again you can get feedback internally, or by recruiting testers, or by having a QA department. I do game development. We do play tests when we're trying to figure out if something is a good idea and we have QA to track the bugs. CI is very useful for coordinating with QA on things, but god help us if we started shipping everything checked in. Not every feature is a winner.

Not saying CD can't be useful in some contexts, but I remain unconvinced it's anything but a niche need. CI is pretty universally useful, but CD? Really depends on what you're shipping and who you're shipping it to.

There are lots of things that QA can't test well. Some bugs can only be detected at scale. If you push every feature immidiately, it's also very easy to roll back a bad feature immidiately. And you can notice and deal with performance issues much more easily than with weekly or monthly releases.

> Minimal code delta means the isolation of any bugs is much easier than if you have to read through six months of patches.

That's going from one extreme to the other.

Just because you don't release every build that passes automated testing doesn't mean you wait six months between prod deployments.

> Where exactly is rapid incremental code delivery at such a premium?

In all fast-changing environments, as well as in early-stage projects that don't a very firm direction yet.