I agree with you.
It would be really cool if you get 1credit per minute. 1Credit if you kill a Human and 2Credits if you kill a Zombie. It would make the Humans really hunt the Zombies. Spectators are not included.
After you collected about 500 Credits you can type in !store or !shop and buy tracers, trails, grenade trails, maybe skinmodels.
~Patan, Daniel