Forms are fun to do and look nice as some have already said but they do not include even close to enough of the dynamics of combat to properly prepare a person for combat. There are no feints, no contact (except for the rare two person form which, again, lacks feints) and no fear of being hit. Also, what about grappling. Grappling is an important factor for combat yet I've never seen a grappling art with a form to practice, only techniques.
Are you sure there is no form in grappling? Do you do rolls? I am sure there is "form" to rolling you just have to analyze it. When you do or at least first learn a takedown or throw don't you go step by step? That can be a form ( A really strange one but still a form.) I may be going over the edge a little bit but isn't there "form" to everything we do in life? There can be "form" when you are driving, cooking, cleaning etc.