I think the idea is that you might spend some points on unit upgrades, but you'd also spend some on getting new units for the combat roster - the idea being you have more choice of what to bring to a particular game than someone whose Crusade has just started out, but the game itself should have reasonably well matched forces.
With that said:
Wyldhunt wrote:Would it be ridiculous of me to create an "add-on" to the crusade rules that forces me to swap out units between games and gives me more reason to spend
RP?
Not at all! It's narrative play, do what you want with it -
as long as you have your opponent's agreement.