Yes! You can use the tool for any purpose, even commercially.
At the moment I have the last version on hold. It includes many new features. Once I find a moment to clean up the code, I'll upload it to github. Anyway any suggestions are welcome.
One suggestion I have: When I hover over the icons, it gives me a description. It would be nice if it did the same with the props (if you used these for specific purposes). And perhaps the ability to save as you go in case you can't complete your schematic in one sitting.
WONDERFUL job. I'm in awe of this product. :)