Convenience? `tar` integrates well with compression tools, but doesn't implement compression itself. This is the epitome of the Unix philosophy. You can just as well pipe its output to any compression tool of your choice, if you prefer not using its CLI.

> why find has a DSL?

Describing an advanced CLI as a DSL is a stretch. But to humour you: flexibility, and because files have many attributes which a good finding tool should expose to the user. Whether you like its CLI or not is a separate topic, but you're mistaking minimalism for simplicity as a requirement of the Unix philosophy. Some tasks are inherently complex, and forcing a tool to be "minimal" at the expense of flexibility would be counterproductive.

Besides, you're free to choose any other tool you like more to find files on your system. The fact GNU `find` is easily replaceable is precisely a sign that it follows the Unix philosophy well. I personally use `fd` and ripgrep more often than `find` these days.

Re: `cat -v`, I hardly know the history behind it, but it doesn't really matter. As a sibling comment mentions, there are no hard rules around this topic, and people will disagree about what it really means, and how a program should be designed. If I had an opinion on the topic of `cat -v`, I would probably argue with Rob Pike about it as well. None of this means that these design principles are not worth upholding, or that we won't make mistakes along the way. But going back on topic, it's a problem when a project like systemd explicitly chooses not to follow these principles.