Crusaders adds a casus belli that gives you temporary bonuses like untiy and ship speed, it is shown in the tooltip/description of the civic.

If you dont see it, perhaps you use a broken translation mod?

I mean i cant understand what this casus belli does. In my translation, when i`m declaring a war it says something like "starts a war to punish heretics of all kinds". What kind of punishment is that?
I took that civil model cuz i thought this casus belli would be something like in real history, when christians tried to take Jerusalem for their own, so, annex everything. But i`m not sure about your version of crusade)
Anyway thx for fast answers

Nevermind, it works exactly like i wanted it to. I`m just annexing every system my ships enter, thx.