Quote from ArcticKitsune
They could always be eaten as seeds (melon and cookie style) or they can be used to power some diesel type engine. Upgraded furnace and similar in a very simplified manner? *shrugs*
I doubt the engine part. Would be cool, but in vanilla Minecraft... it sounds a little less minecrafty. I knew seeds are edible, I hope that in Minecraft too. I hope you could actually farm these things too.