They are thin - a leather laminate over man made materials. As such I would not use them as boots, but as part of a costume. With care they will serve multiple uses to the RenFest, ITLAPD, and Halloween. Just my opinion.
I have not yet purchased these boots; I need to consider carefully the construction and material quality of them. The leather and the laces appear to be thin and flimsy in the photos.... I do not expect they will have much of a lifetime with more than very occasional use. If they deteriorate too much with the first use in the usually wet and muddy RenFair environment, they would not be worth the price... Just my opinion.