Are you investing in equipment or are you investing in your understanding of craft?
You can increase you understanding of craft by learning to work your camera and by learning the all you can about photography. You can read books, you can take classes, you can do both.
Your equipment can only take you so far, it’s usefulness is limited, it can be stolen or broken and it eventually needs to be replaced.
Your understanding and application of craft can take you as far as you’d like to go, it’s usefulness is unlimited, it can’t be stolen or broken and it’s irreplaceable.
In my mind, investing in your understanding of craft is a better investment.