"So now you have the friction of six ball bearings.

The 38 case and bearing only has one contact point.

Why would you think grinding the BAS is a bad idea?"

With the 38 case,the BAS rides on a single center point.with the 6 bearings, the
BAS's surface has full contact.

Using the 38 case and single bearing,the BAS usually has to be ground to make up for the 38 case and bearing,
If the case and bearing are removed,the BAS is now to short for %100 function of the firing pin.

As far as 6 friction points,I use a white grease that I use on my M1 Grand and M1A.(military uses this stuff)
the size of the spacer keeps the BAS from mashing down on the bearings,yet full function of the firing pin.