Personally I am not happy with this at all. Firstly, if the POH says not to do it, then don't do it. Also, side-slipping an aeroplane is no substitute for a well set up approach, and this is what you should be taught first.
I believe that the issue with a high tail Cessna is that the elevator will be partially blanked off by the flaps, which is not ideal when you are low and slow on approach.
What is good for one aeroplane is not necessarily good for another. Take some other advice at the club first.