My understanding and experience is that the standard Python installation doesn’t see the Panda libraries, hence the need for ppython.
That’s actually the exact page I used to “uninstall” 1.7.2 before putting 1.8 on my machine. I don’t think that’s all there is to it because my ppython still thinks it’s 2.5 
Yeah it seems like a catch-22: wxpython needs python 2.6 but python 2.6 doesn’t see panda so using python 2.6 isn’t an option.