Yes. Setting up punches, finishing combinations, countering the wrestler, controlling range, finishing the fight. These are all area's where the kick is vitally effective.
Using a kick you can keep your guessing as to what you're gameplan is. You can come out and throw the occassional kick at the beginning/end of a combination, or on their own as individual attacks. Another advantage of the kick is that if you are landing with any regularity, and they're damaging, it has the tendancy to make your opponent A. skittish and unwilling to commit, or B. Dangerously aggressive and overcommittal.
When attacking the legs, you can limit mobility and explosiveness, making the opponent less able to burst for a takedown, or less able to quickly sprawl, also, less able to properly balance and pivot.
Attacking the head/body are very situational. Attacking the head should only be done (IMO) when you "feel it" so to speak. The same way a grappler can feel when its the right time to shoot. Attacking the body should only be done when your opponent's attention is elsewhere, i.e. evading punches or reseting. Attacking the body puts your leg in the perfect position for a single leg takedown attempt.
Forrest Griffin vs Rampage Jackson
Pedro Rizzo vs Ken Shamrock
Almost every CroCop PrideFC fight.
Shogun vs Machida 1 or 2.
Sig courtesy of that photo-matic magician limba
I went out the way that I fight. I went out on my shield. Thatís it. Done. --Chuck Liddell
My goal is to end my opponent --Carlos Condit