Traditional Wushu (commonly known as kung fu) is the fighting arts of China, some of which are very old, but all of which are designed to be very effective as a fighting and self defense method.
Modern Wushu was created by the Communist government in China beginning in the 1950s, based on elements taken from traditional wushu. The purpose of modern wushu was very deliberately meant to be as a Chinese national sport, and performance art, and contains a lot of material that is not effective in a fighting art. There are a lot of gymnastic type movements, asthetic posturing, and extreme kinds of techiques that look good to an audience and impress a judge in the same way that a gymnastics routine is impressive. Successful competitors in modern wushu are usually elite athletes, and in this they are very impressive.
There is no pretending in Modern Wushu to be a fighting art, however. Yes, on a superficial level, it does look like fighting traditional wushu. But it is not. There are crucial differences in how basic techniques and stances and whatnot are done, that are meant to make the movement prettier, but it also often diminishes its effectiveness. More importantly, the understanding of how the movement would be applied in a real fight is definitely NOT a focus in typical modern wushu training. Usually, modern wushu champions simply do not understand how they would even apply the movements that they know, even if they could hypothetically be useful. They have simply memorized and mastered their performance of a fixed athletic routine.
The dangers in modern wushu are that it can lead to injuries. Sure, this can happen in any martial art. But I think the injuries that happen in modern wushu are avoidable. They often push the limits of what the body can do, all in the name of performance. And inevitably, people get hurt from it. The way certain things are done simply lead to injury. When landing from arial techniques and gymnastic moves, they often like to land hard in a dramatic stance. The problem is, this leads to foot injuries and fallen arches which can plague you in later years. So some injuries are gradual and you don't realize they are happening until it's too late. Other injuries are acute and happen because you are simply trying to do something that is too extreme, with the only benefit being to impress an audience and win a medal. So you can end up with pulled or torn muscles, sprains, twisted ankles, fallen arches, chronic lower back pain, etc.
Modern wushu can be impressive to watch, the competitors are outstanding athletes. But it is not fighting kung fu, altho I have heard that there is a movement among some people to try and bring the fighting usefulness back into modern wushu. How successful they have been, I do not know. But modern wushu, at the international competition level, is still controlled by the Chinese government, and they write and re-write the competition rules as they see fit. They create the new forms that competitors are expected to learn if they want to be successful at the international level. And they are the ones who are often pushing the athletes to more and more extreme movements that lead to injuries. And these people are often old men sitting behind a desk coming up with these ideas out of their imagination. They can't do it themselves, they won't even try, but they expect the athletes to do them. Even the premier groups like the Beijing Wushu Team are wrapping their ankles and knees and stuff, because they are chronically injured. My sifu, who trained with them in the 1980s, said that was not the case back then, and it is disturbing to see it happening now.
So I guess you need to ask yourself, what does your daughter want? Does she want real self defense skills? Then do a traditional Chinese martial art that is designed for this and trains appropriately.
Does she want to be a gymnastics competitor with a martial arts flavor, and a willingness to risk injury for the sake of performance? Then she ought to do modern wushu.
Either method can develop someone into a very strong athlete. But the end purpose is very different.
