The question is: Is planning ERA3 on a daily basis legal?
Companies will plan for ERA3 because the cost is lower.
I think if a company could plan a RCFP on a daily basis and the pilots accepting it they would.
I don't mind taking 3% if the conditions are suited for it. Personally I want 5% when the conditions enroute are bad or my MNPS Flight level has a good chance of being lower.