I'll add one factor which the other already good answers didn't mention in detail: **weight**. Modern cars have several dozens of fuses, each one weighing a couple of grams. Imagine replacing them with even the smallest automatic breaker you find, for example [this](https://docs.rs-online.com/ba15/0900766b8002996e.pdf): [![enter image description here][1]][1] and look at the specs: [![enter image description here][2]][2] It **weighs ten times more**! Not mentioning it's much bigger and the endurance against the environmental conditions is nowhere suitable for a car. And improving its tolerance against an adverse environment will probably add still more weight. Bottom line: you'll end up adding kilograms of weight for no more than a very small convenience (resetting a breaker instead to change a blown fuse, event which in normal car operation is quite rare). In exchange you will have a heavier and more expensive car. [1]: https://i.sstatic.net/lbxFM.png [2]: https://i.sstatic.net/oKQDF.png