Humans have ridden horses for a long time. In the modern world, it happens far less often. Still, there are a lot of places in the world where horseback is the primary way to get around. If you go to one of those places, you don't want to get stranded just because you can't get around.
Horseback riding can be a fun and healthful activity. Fresh air is good for you, even if it does smell of horse. It also feels great to commune with these magnificent creatures. Just be aware that horses have a culture of their own and you will have to learn that culture if you are going to get along with them.
There are plenty of places to learn horseback riding in most areas. Most are private stables that supplement their income through these training activities. There are some agricultural schools that offer classes. Since there is no need to get a horse license, you can also learn just by having a buddy or family member teach you, like in the old days.