After recent repair - noticed the right rear quarter window pane has its grid worn out.

I was in a rear accident - and I took my 2012 Prius to my local body shop can to fix the rear frame.

During their repair - since they were replace the outer rear frame - they had to remove and reinstall the right rear quarter window panel of the car - the one with what looks like defroster grids.

When I got the car back - I noticed some of the grid lines were a little worn out.

So I have two questions:

#1 What exactly do these grid lines do - are they defrosters? They have it only the right side of the window - the left side of the window doesn't have any grids.

#2 Should I be concerned about this wear in terms of functionality of the car, or is this just some cosmetic issue?

Also the body shop - told me they wouldn't mess with the grid - so it must have been natural wear-down of the grid lines - is that possible?

I have attached a photo of what I'm the window pane in question.

 

Really? Isn't the radio antenna the little black spindle sitting in the back roof?

 

I see... Well I don't think my Prius even had HD Radio built-in capabilities to begin with (at least my factory-built CD Player unit doesn't seem to support it).

If that's the case - even if this grid line on this window kind of fades out - I'm not really using it to begin with... so it's a none issue - right?