Small hacking seconds hand - why different colors?

I just bought a Portugieser Automatic 40 in Rose Gold -www.iwc.com/us/en/watch-collections/portugieser/iw358306-portugieser-automatic-40.html

I love this watch, but wonder why is the small hacking seconds hand blue and not gold? I have noticed that some gold watches in the portugieser line have a gold second hand and some have a blue and some have both... Is there a reason or is it just to change things up?

Here is the Portugieser Automatic in Rose Gold with gold seconds hand -www.iwc.com/us/en/watch-collections/portugieser/iw500701-portugieser-automatic.html

Finally, here is a Portugieser Chronograph with both gold and blue small hands - www.iwc.com/us/en/watch-collections/portugieser/iw371611-portugieser-chronograph.html

Congratulations on your beautiful Portugieser!!

In the case of the Chronograph, the the seconds and minute counter hands are matching blue, for ease of use.......