Are patterns (forms) useful in Martial Arts?

Many practitioners of other martial arts seem keen to question the usefulness of learning patterns (forms). Particularly those training in MMA (Mixed Martial Arts) and other purely combat based systems. The argument runs that learning patterns does not in any way aid fighting ability. There are two problems with this.

Firstly, Taekwondo is not just about fighting & self defense. It is a complete martial art in that the student is learning a wide range of skills that apply to situations in life other than combat situations. Mental discipline and physical fitness aid the Taekwondo student in most aspects of their lives. Learning patterns helps with mental discipline, gives the student a means to practice when alone and is of course the backbone of the grading syllabus. If Taekwondo were merely about combat ability a grading/belts system would not be needed. The senior students would be simply measured by their success in defeating other opponents.

Secondly, patterns, when executed correctly give the student the chance to practice techniques which are simply too dangerous to try out on a real opponent. The patterns teach us how to combine techniques effectively (block/counter attack). For techniques to become second nature and applicable in real situations, you need to have practiced them repetitively hundreds/thousands of times so that your brain can react instantly with the appropriate technique in a given situation. Taekwondo Poomse's are designed to simulate complex situations in which the student has to deal with multiple assailants coming at him from all directions - something that without doubt can be carried over into real defensive situations.