Squad change orders allow players to change the composition of their squads on a whim.
But it’s usually used to correct some mistake like accidentally picking the secondary weapons slot instead of backpacks.
Thus, if you’ve already planned how you would progress through a campaign, chances are, you’re unlikely to make any adjustments to your squads once you run through it.
Now you have about a dozen squad change orders sitting around being pretty. Why not have the ability to convert them into level ups for squads?