The point is that the mere fuzziness of a given line is not a reason to doubt that a legal distinction can be drawn. All OP did was to show that the line is fuzzy. I was criticizing OP's argument, not presenting a positive argument by analogy. Perhaps a legal line can't be drawn between money and speech, but if so, this can't be the case merely because the logical boundary between the two is fuzzy.

In fact, any disanalogy only lends further support to my point. If the First Amendment doesn't even permit you to say anything you like, then it surely doesn't permit you to spend money any way you like!

If it were really impossible to draw a line between money and speech, then the First Amendment would protect all kinds of dubious financial schemes. It doesn't.