It doesn’t necessarily mean you have the skills, but it can inform the process. I can’t think of a case where knowing your materials would be detrimental to working with them.
That's fair, it certainly helps. If you don't understand how all the parsing bits work you might make something that sucks to parse which can lead to confusing syntax. But it doesn't guarantee you can do the design phase.
Sometimes a little knowledge is more dangerous than ignorance.