Nowadays, we can notice that manufacturers shows Wi-Fi support and separately Wi-Fi Direct support.
So, let's find differences between Wi-Fi and Wi-Fi Direct?
There are not global differences when we talk about simple Wi-Fi. To start sharing Wi-Fi you must use Wi-Fi spot, you can also create hot spot using your tablet or smartphone. The basic principle of functioning of Wi-Fi router is the fact that one device get data by one channel. To connect to Wi-Fi router you must use safe or free connection. If the connection is safe, you can connect only in case you know password.
If your device support Wi-Fi Direct, you can use it as virtual hot spot without any additional settings or software (you can choose safe connection or without password). The pros of WI-Fi Direct is that you are able to create hot spot in one click, but speaking fluently, much easier way is to buy a router and use it every day.