When should I make skirmishers as germany?

Hi,

I'm new to ranked supremacy 1V1 (low ELO) and i'm maining germany.

My usual strategy is to ff and build a mix of falconets, war wagons and some uhlans. The falconets obliterate the ennemy infantry while the war wagons protect them from the ennemy cavalry and culverines. The uhlans serve as a reserve and a distraction. I know that as a german I should include skirmishers in my build but I've no idea why. The culverines are arguably as good to kill infantry (probably less damage but much more range so I can force the ennemy to attack my WW frontline) and can also be used as siege weapons. WW are maybe less effective against infantry but they're not bad at all against them, with all the hp upgrades they're so tanky they survive being targeted by museteers so I can just send them to the hospital and minimize losses.