First. I've already stated several times I didn't expect anyone to take the idea seriously.
But, as you seem to have let me respond to your logic.
1% means that I get to double down on 100 of his posts before I'm depleted. He's already posted over 250 post this year alone, of which well over half are meaningless. It would have no effect.
But equally, there are occasions when I feel I'd like to double upvote a particularly inciteful, or just helpful, or surprising post.
Many people including myself, have posted replies saying: "I wish I could give you two upvotes for this".
Should that also "cost" me 1% of my "wealth"?
And finally your whole "buying votes" narrative is a crock. A strawman. I would not be buying votes to win an election; or gain influence; or for personal gain; nor anything similar.
The idea was to address a community problem that currently has no solution.
If the notion had any merit at all, it would be applied across the board; it would empower everyone who can vote, to apply one extra vote (up or down) to a post they chose as worthy, (say) once a day, at the cost of either reducing their own XP tally; or perhaps the extra vote comes out of their existing daily allowance. Or both.
A quite different suggestion to the one you've constructed, to knock down.