Unfortunately, MLMs are legal, and since a service is being done for pay (ads count as a 'service') then this is probably legit.
But I thought the point of Brave was to pay content authors. Wouldn't a simpler and more consistent solution be to make it so that if a viewer received a payment for viewing ads (man that is hard to type) that the money is held in escrow until they pay it out to a site the user has visited?]