Lot of answers so far seem to have missed the points being made in the book the article references.
If you have the ability to ship things fast - and so do regularly - you will find that your releases:
- Have a small blast radius if there are bugs, because how much blast can you have in an hour's work versus a quarter's?
- The tooling that you build to let you go fast will tell you that a blast is indeed happening right now
- Your Mean-Time-To-Resolution (MTTR) is lower because you can just roll it back. It's not days or weeks of work to get a rollback out, it's minutes.
- That having a culture of being able to release continuously and quickly allows you to go fast, and the occasional breakage is tolerable, because the cost is low.
You can go slow if you want. And if you don't have LEST metrics or have slow release processes you must, but if you work to get to the point where you are able to move fast, you'll find that you break things less and fix them quicker when they do break.
The alternative is you still break things, but the problems incurred are much, much greater.
Also note: there are some environments where continuous deployment is never going to be an option or desirable. Thankfully these environments tend to be ones where the market will tolerate the higher costs of formal methods and a more deliberative quality control process (medical devices, aerospace, nuclear reactors, etc.).