Yet I got confused the first time ever some README told me to run "npm install blah". WTF is NPM? I didn't care, really, I just wanted to use blah. Conversely, later I worked with Node devs who would not know where to even start if I asked them to install a C++ toolchain.
The point is don't assume too much about the background of the people reading your instructions. They don't have in their heads the same stuff you take for granted.
I've found instances where some documentation instructions pointed to run Maven, and the commands worked in their machine because Maven is highly dependent on customizations and local cache. But it failed in other machines that didn't have this parameter configured, or that package version cached locally. And trust me, Maven can be _very_ obtuse and hard to troubleshoot, too much implicit magic happening.
Testing in a clean container or VM would have raised those issues before the readme was written and published. Hence my point stands, testing commands in a clean system is akin to testing a web page in a private tab, to prevent any previous local state polluting the test.
Frankly I prefer the 10,000 approach suggested by XKCD: https://xkcd.com/1053/