Though I have no metaphysical beliefs, on the topic of sigils, I actually find them quite fascinating and wonder if they might be beneficial to someone without such beliefs. When it comes to hypnosis, the mind does better understanding packaging the intent of a complex action into one thing, rather than in steps. Creating a sigil is interesting as a way of putting work into understanding a complex idea and producing a simple object to focus on in meditation which symbolizes that action. I don't know of another way to accomplish that with regular forms of hypnosis other than to simply "do it" and understand already what you're going for.