pistoriusp's comment isn't about trip.js, it's about overall design of sites. The goal of a UX engineer is to make things like trip.js obsolete. The design should be clean and self explanatory.
I 100% agree with your comment. That is most definitely the goal of a UX engineer. However it's kind of like striving for perfection, it's impossible. If anything a really good UX engineer shoots for that 100% and fills in the rest with these types of tools. Can anyone here point to a complex webapp that doesn't have some kind of instructions system?