I'm not going to downvote you, but I do disagree. Personally I think you should be properly planning and testing as you say AND using automation. They're not mutually exclusive.
Configuring a CI tool really isn't rocket science. If you're a software developer, and you understand the concept of taking the source, converting it to a working product, and ideally running some form of tests against it then you understand how to configure a CI tool. There's nothing magic about it - it's just a case of taking what you already do manually and getting the CI tool to do the same thing.
There's a ton of different reasons for using CI, ranging from getting immediate feedback about problems when working in a team through to ensuring consistency when creating builds. If you deploy directly from your development machine rather than a CI system, for example, you're asking for trouble. I'm not saying you'll definitely have issues, but there's at least the chance that you make a mistake and accidentally leave in debugging statements or work in progress that shouldn't be there. Obviously you shouldn't do this, and you should 100% test everything you do, along with every possible thing it can affect, but people aren't perfect and make mistakes. If you use a CI system these kind of issues pretty much go away.
So yes, you're completely correct that people should properly plan their work, and then make sure that they test it properly by hand. But that doesn't also prevent you from using automated testing and CI systems. Both are part and parcel with professional software development to my mind.
I'm able to take the time to reply to this over lunch because I spent the time 5+ years ago configuring a CI tool and rarely have to worry about it.