Striking in what context┐ Striking in a Boxing match┐ A Kickbox, Muay Thai match┐ In MMA┐ On the street for self defense┐
Rules and circumstances determine the necessity of the way of striking.
Gloves for example influence your defensive work and therefore subsequently also your offensive work. Big gloves like in Boxing/Kickboxing/Muay Thai enable to easily block striking attacks, which is much harder with MMA gloves and even more harder bare knuckled, so in each case the offense has to be adapted. A rule whether the fight continues on the ground influences on how much you have to worry about your balance. In Muay Thai you don't have to worry that much, so fighters throw a lot of high kicks, because if it hits the head it almost equals a win via KO. In MMA people are more cautious in that aspect, because a high kick makes vulnerable to a take down. It's still an option if you're either confident in fighting on the ground or at least in knowing how to stand up again. On the street you absolutely want to avoid to go to the ground, because that means you lose one dimension of mobility and you never know whether your opponent doesn't have some friends around that stomp on your head while you are busy grappling with him.
Then, what consequences has your punch to you┐ Bandaged and gloved fists are well protected, bare knuckles were not evolved by nature to hit hard targets as a forehead and can easily brake and you don't want the broken teeth of your opponent cut open your fingers and contaminate you with any diseases. So in self defense open hand strikes and slaps have a bigger value than in a sportive competition with gloves. Then again, slaps can directly be transferred into grips if the opponent wears clothes.
And so on...
So the answer to the topic question is not so easy to be found as it seems on first glances. There are many factors that have an influence.