Are you asking why buy the console with more announced exclusive games than another console?
Only on Xbox One (14 games)
• Below
• Black Tusk Studio game
• Crimson Dragon
• D4
• Dead Rising 3
• Forza Motorsport 5
• Halo
• Killer Instinct
• Kinect Sports Rivals
• Powerstar Golf
• Quantum Break
• Rabbids Invasion
• Ryse: Son of Rome
• Sunset Overdrive
Only On PS4 (10 games)
• Basement Crawl
• Deep Down
• Driveclub
• Galak-Z
• Infamous: Second Son
• Killzone: Shadow Fall
• Knack
• The Order 1886
• Secret Ponchos
• Super Stardust
Maybe your game tastes are more aligned with the PS4, but if you're talking strict number of games...why get a PS4?