Question about scout flush into knights

Noob question here, but I haven't been able to find a direct answer anywhere. I've been practicing with the Cicero build orders scenario and I'm wondering under what situations would it make the most sense to go scouts into knights (as opposed to archers/crossbows or skirms). As far as I can tell, my opponent will create a lot of spearmen to counter my scouts, and knights don't necessarily seem the most efficient choice against that army composition. Is it that knights are really that OP even against spears (but what about pikes)? Or maybe it makes sense with civs with cavalry or relevant eco bonuses? Or is it that the goal is to raid rather than engage the spears/pikes directly? Or maybe it's a strategy to just finish the job assuming the flush was very successful at harming my opponents' eco? Anyways, I usually follow a scout rush with crossbowmen, so I was wondering under what circumstances going into knights might a be better strategy. Thanks!