Chapter Champion

[VulkansApprentice]

Ok, I'm going crazy here. I've been going back and forth over the options for Honor Guard, and I just can't shake what the option for a Chapter Champion to replace his bolter with a combat blade is for. I know that Calgar has double fists and a power sword, and he can choose to forgo the fists for attacks at initiative with the sword. But reading through the options for the champion I'm coming up with the following;

-He is already armed with a power weapon, pistol, and bolter, base.

-ANY MODEL has the option to TAKE a relic blade, not REPLACE something with a relic blade, so taking the upgrade would give him a relic blade, bolter, pistol, and power weapon.

-Now I can understand that if he had to REPLACE his power sword with the relic blade that he would be down to a bolter, relic blade, and pistol. Now he would only have his base attacks with the relic. However, if he replaced the bolter with the blade he could have 3 attacks at S6 with the relic, or 4 attacks (non-S6 non-PW)) with the pistol and combat blade. (I guess useful for an extra attack against horde? Though I'd rather have the sure kills from the relic)

-But seeing as how he already has the relic blade and bolter and pistol and PW, why need the blade? Is it only if he REPLACES his PW with a TH, then he would need the blade to double with pistol, so he could then attack at initiative?

Is there any other reason for the combat blade, or am I just driving myself crazy over nothing?

Also, what sense does it make that a company champion gets a combat shield, when the chapter champion can't?