It's a clever way to finish.
Firstly, what harm can it do? The worst thing that the jurors will think is that well she would say that.
She's going to be complimentary. Obviously the defence will make sure of that.
Secondly, what of those who are on the fence about his guilt/innocence.
This could be the thing that sways them to find him innocent: oh well I'm unsure, can't really decide one way or another but he seems reformed now so give him the benefit of the doubt.
If it's the last thing they hear that also favours Brand.
They're asking 12 members of the public who are human beings at the end of the day not experts.
Not sure about your last point though about Gisele P.