As you have experienced, as long as I participated in the bounty campaign I also had never received a prize in the form of Eth directly, the most often being tokens from the project that we followed. Actually that doesn't matter, as long as the price of the token when entering the market the price doesn't go too far. indeed it may be easier and more profitable if we are paid directly with eth, but in reality I have not found a project that directly pays Eth.