If we have a system that allows you to buy votes from other people, how is that any more of a flaw than simply using our current method of voting and allowing t

If we have a system that allows you to buy votes from other people, how is that any more of a flaw than simply using our current method of voting and allowing the same type of vote buying? It sounds like you are saying that a system that allows you to buy other people's votes skews toward rich people. We don't outright allow that today unless you count advertising. With the quadratic system proposed, rich would have to choose between advertising or putting more money into the voter pool (is distributed to everyone and thus increases the voting power of the poorer majority).