Bitchimin over brick or render.

Just been chatting to a 'damp expert' about quick check solutions.
He said he renders wall (inside ) with sbr then paints bitchimin with blinded sand.
I've always done it the other way with bitchimin painted onto brickwork then sbr render over the top and skim..

I understand it's certainly not the best method, but which of the above is 'better'