Additional user fields during Commerce guest checkout?

[opentype]

Both question and feedback:

I just noticed, that when I check out as guest in Commerce, the sign up form is not the same as the regular site signup, but offers additional members fields. 
This is really weird. In my case, those are optional fields set up for my forum members to give them the chance to tell other community members a little bit more about themselves. Wanting this information from store customers who just want buy a book for example is really weird and might even make them suspicious and cancel the order.  

1. Is this intentional? Shouldn’t the Commerce sign up form be the same as the site sign up form?
2. What conditions are used to show these fields there? Because it’s not all fields I have set up, but I couldn’t see any logic to it. 

[opentype]

Problem identified via ticket: 
When Quick Registration is turned on, the setting to show or hide fields during registration is hidden. This can lead to inconsistent registration screens (site vs. Commerce) and no option to correct this.