A perfect proof for GP's/TFA's point.

To this I'll only add that "follow these instructions carefully + magic happens" works only for ~6 months after a tutorial is published, longer than that and some dependency or toolchain update somewhere is bound to break the instructions in a way incomprehensible to a novice.

Not only to a novice. I was recently contracted to update a client from rails 4 to 5.2, which included updating sprockets, which ended with us downloading the source code of all the gems to because nobody could figure out why the html would contain the correct url for the asset, but rake would first produce the file during asset precompilation and then later delete it during cleanup. 2 days wasted on broken magic...

Oh I agree, my current preferred way to use Rails is as an API with no frontend at all.