The sensible person is the one who understands that such ponzi schemes is not good for the bitcoin community.
It concentrates money into the hands of a few. Promotes economic divide.
Such a thing is beneficial for no one other than the person who actually makes profit from this, that is the owner of the site.
I don't think this promotes economic divide in anyway.. at the end of the day, whether the owner stole the money or not, all kinds of people will lose money.
it might be just as beneficial for others too if they takes risk first and plays safe next. re-investing their profit, for example. and not everyone is foolish enough to invest all they have on the last two or three days.