Strange Rear brake conversion on track frame, on a £1,300 quid bike good or bad?

I guess I am wondering why bodge on a rear break, what’s the point “apart from the obvious “
The female owner did not seem to care weather the bike was track or road, she was more into the colour.
I totally understand bodging a break to an old track bike if you have to, but not a brand new track frame form a shop.

is she riding a bike?