The aim of WPS Connect is to check if the specific router is vulnerable to a PIN by default. Many routers installed by internet service providers have vulnerabilities. With this app, you can check if your own router is vulnerable and change the password accordingly.
It's very important to keep in mind that in order to use WPS Connect, you need a rooted device.
WPS Connect is a very useful tool for checking if your router's password is completely secure ... though it obviously also has other uses.