Senna Dog
The comments that you quoted in your post are, each and every one of them, utter horse**** other than the "Spinning is great fun", IMHO of course...
Consider that spinning used to be in the syllabus for a PPL - at least in NZ and, I believe in the UK although I am not entirely sure about that.
You now have your PPL and looking to improve various aspects of your flying skills and repertoire. Learning to spin an aeroplane safely not only will teach you how to recover should you ever enter a spin inadvertently, but is also an intelligent precursor to starting aerobatics, should you be interested in that.
Even if you don't particularly like it, spin training will never be detrimental to your flying skills and it may awaken your interest in a different type of flying.
Enjoy.