This is not a question of style, but background and prejudice. As an Okinawan Karate-ka, we don't kick high, to long and to easy to pick off. As a Jujutsu-ist, we love the hight kicks because they are easier to handle. So I have to agree with "Isshin" on this regard. Practice high, apply low, is the principle we use. You don't need to knock someone out when you kick them. lower kicks are generally quicker, so they can be powerful too. A good kick to the inside of an attackers inner chin and he will present his face to you, which leaves him open.
I will not deny that high kicks can be used, but from my view, it takes longer to kick to the head than leg, closest weapon to the closest target. Also, the longer you are on 1 leg, the more off balance you are for counters.
If you are good enough and practice high kicks go for it, but just remember, if you have been training with people within the same style, you may not see what others are seeing. Its always good to get anothers perspective.
Just a note, I saw a Karate student and a Jujutsu student arguing at a seminar, which led to the disagreement about high kicks. The Karate-ka didn't know what the BJJ had, so when he bet he could knock out the Jujutsu-ist with a kick and they went to the center mat. As the Karate-KA kicked the Jujutsu-ist 'speared' his planted knee. It was not pretty, all sorts of knee damage, and ligament damage. The Karate guy was out for a year I was told, and now he can't kick high. Both were Brown Belts, and neither had great control as you can tell, both trying to show who is best. They both lost, as the Jujutsu-ist didn't prove his point as everybody felt what he did was unjust. Sharing information, is so much more important, than trying toprove your point. If you want to kick high by all means do so, but understand we are not criticising your style but how we view kicking