Laptops are a wonderful way your computer can be taken around in fact practically anywhere.
You can even use them on the beach. A lap top has a screen, a mousepad, and instead of a mouse you have a track pad or in some cases a trackball.
As you can imagine with so many people using laptops while on planes and while travelling on trains and other forms of transport the laptop can operate when charged without being connected to power outlet.
The power adapter charges them when they run out of battery power. With all these features to recommend them, laptops are not as powerful as desktop computers but with all the improvements and developments a very good laptop can perform almost as well as a desktop computer and better than some low-end desktop computers.
The laptops can also have usb ports which allows a mouse and other adapters and connections to be used.