With voting to elect a representative, the point is to choose whoever you feel best represents your interests. A conflict of interest does not matter because the self interest is kind of the point.
With voting on passing legislation, the point is to choose what best represents the interests of your constituents, conflicts of interest matter because they may cause you to not properly represent the interests of your constituents. Self interest is not supposed to be the point.
With voting on passing legislation, the point is to choose what best represents the interests of your constituents, conflicts of interest matter because they may cause you to not properly represent the interests of your constituents. Self interest is not supposed to be the point.