Uses? Also charcoal is essentially coal, and wood is an ancient element so it will not change.
Well... In my opinion it's too much like coal, but I am aware that coal and charcoal are two different things. Maybe it could be used as a reagent for gunpowder? (charcoal/potassium nitrate/sulfur) But I don't see the devs adding it for that reason alone. Not to mention we have no KNO3 or sulfur...
Also, it would probably break some saves in some way.
Or even better, if the WOOD/PLNT charring feature from Jacob1's mod gets put into the official, just make a block of coal surrounded by wood that had been heated to around 300 degrees celsius and cooled down to room temperature. (The cooling down part is so that the coal won't glow).
I didn't realise that was in the mod. Sweet.
Even better, I was the one who suggested it.