What is the point of having magic in a fantasy world if the characters in it don't use it?

When I say "don't use it," I mean that a lot of the time magic is just used for flashy fights, or convenient plot devices. What I want to know is, why do a lot of fantasy worlds have magic if the people living in those worlds don't use it to improve their lives at all? A good example would be something like the Harry Potter series. In that series, they have all of these convenient spells and potions that make life easier. For example teleportation, the Marauder's Map, date rape drugs, etc. Yet, somehow all of the magic users in that world are still using modern technology. Why? Why not just use magic for everything? <br><br>Magic is usually so overpowered that it would cause a lot of changes in society that most people don't seem to take into account. That's what I mean by "improve their lives." I feel like that's a big part of worldbuilding, magic is a part of the world that the people live in, so they're going to use it because it makes their lives better. So, why don't characters in most fantasy worlds use magic to make their lives better? <br><br>Magic should change the world, otherwise it's just a cool gimmick.