Using Reiki symbols

[Lucky]

Over the course of my 4 year journey I have completed reiki level 2. I see this as something that takes time to really adjust to and digest before moving on to Master/teacher level, so I'm in no rush. However I haven't stopped learning, studying or questioning about Reiki. I picked up a book about Reiki today that shares a modern perspective on this ancient practice and it got me thinking...

There really are many variations of the history of how reiki as a practice came to be, not to mention how it was brought to the Western world in a way that made it more acceptable. Anyway, what got my attention once again was the use and importance of symbols in Reiki. It has been said Dr. Usui did not even use symbols in his practice (as some say), also how reiki is an intelligent energy and knows where to go, also it stresses to practitioners to detach from the outcome of a session. With that being said, why do we use so many different symbols for different purposes? Isn't that using our intention (through the meaning of each symbol)? Do we have any business in placing our intention through a symbol at all when this energy is supposedly divinely guided?

I'm open to opinions on these topics, as I'm trying to learn and formulate what I feel to be true. It's not my intention at all to undermine the practice of Reiki or how any practitioners conduct a session, nor is it my intention to start a heated debate. Other than that, your thoughts on this?