> 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.