Why is standard time used in the world?

If you understand what the standard time is, then in simple words, these are 24 zones into which our planet is divided. And this was done so that in different parts of the planet the day was approximately the same, so that the sunrise and sunset would be at about the same time, at least in the aisles of the same parallel. Also, standard time exists in order to localize a specific territory and establish a convenient time calculation there, for example, so that relatively small countries are in the side-altars of the same time.