Yes! Every single point you earn today goes toward the total points your team earns. Whichever City earns the most points today is the Splatterday Champion and next week is displayed at the top of the Frame of Glory posessing the cool TKS "Dark Knight" virtual trophy! This means even playing part of the hour today will really help your team win! Obviously the more wins you get, the more you help.
In addition to Team Battle, placing in the top three today earns you the yellow shirt and placing in the top 30 today earns you the Frame of Glory.