any reward system that you are describing MUST be small otherwise that coin is not even worth your "holding".

it is a very simple supply and demand rule here too. if you distribute a lot of coins for free among people who are simply holding some amount, that means you are flooding the market with a large amount of supply. and that can kill the price.

in other words if you find a coin that gives you profit for holding and that amount is high, there is a pretty good chance that in long run you will lose a lot of money because the price of it will tank hard in long term.