No sense in re-inventing the wheel. There's many hundreds of strip canoes and kayaks with a couple layers of cloth and epoxy on the bottom and they hold up fine. You do pick them up unless you're on grass or a very fine sandy beach. Graphite powder is not going to stop a scratch if you land on a barnacle cover rock. You just fill the scratch when you get home. Most builders are concerned with weight , but if that's no problem, a thick build-up layer (of anything) on the bottom is better than a thin one.

I'm sure graphite lubricates, but I doubt it's going to create a surface that allows to be careless where you land. However, graphite does create a nice black look if that's what you want.