It gives you another option, should you choose to exercise it. If you have a TROPHY token to transfer to @lordnigel, OR if you were awarded one in this tournament and have not yet redeemed it, you can use it to purchase the Level 1 "book of lost spell" from the item shop -- simply comment on the item shop post that you want to purchase the book and how you're paying for it.

Once you purchase the book, you may use the !special command -- that will make you attempt an attack that has a lower rate of success than your strong/risky attack, but if successful, counts as a roll of 15.