The fact this is even a question shows me how many engineers are just cargo culting whatever they hear someone else say. If you can't understand that a toy project has different trade offs than the NSA you really shouldn't be engineering anything, trade offs are the entire job. Nobody is going to spend the time to implement this guide instead of importing a library.
I think this is unnecessarily harsh. Most of the people who implement cryptographic systems are professional engineers, and are not otherwise incorrect in evaluating their skillsets or capabilities. The problem isn't cargo culting, but the fact that cryptography is much more subtle and un-engineering-like that the rest of our discipline.
