Very suspicious. There is no proof of payment from this campaign.
this is very dangerous part of data theft.
you should wait for an answer from the OP on this suspicion.
If you are waiting for paiement proof to join the campaign, i can advice you to try it by yourself, as nothing is garanted here. Op is an unknown user providing unverified information for unknown reasons. He is probably willing to thief personal info using the apply form or just promote something using shady methods.
As no partnership with brave browser is confirmed, op is a suspecious profile and community should be aware dealing with him.