I only use cinnamon on french toast
No it is not practical to use as a fungicide, or rooting hormone or.....

People sprinkle it on top of the media in seedling flats to help control damping off. I have no idea if it works or if using chamomile tea works -another folk remedy.

Another one is tea tree oil, which I actually resorted to a few times... I only have anecdotal evidence for the tea tree oil but it worked for me! I had some begonia leaves that I was trying to propagate and they kept getting moldy, as did the little wooden supports (ok, toothpicks!) that I was using to prop up the plastic... so I put tea tree oil on them with Q-tips and the mold went away!