You can participate in these campaigns, but these campaigns are for reputable and skilled users. Like DT members, moderators and people that are respected in the community, they deceive to be paid in real cryptocurrencies.
No, such bounty are not for deceiving or mainly for reputable members of the forum. The last time I checked anyone who's a good posted can participate in the bounty that pay in Ethereum or bitcoin and I think the reason behind this switch of payment was because some project owner believe bounty hunters are behind the down in price of most new project.