About F-secure firewall

I wonder if there is any use of bying any kind of software from F-secure,since I´ve noticed that this kind of software cooperates with Windows Firewall.

Doesn´t F-secure misses the point if they uses a quite known and weak firewall for their services? In my terms it is so,but I may be wrong. If there is someone that can put all the facts on the table it wold be fine.