By "rewards" I meant fuel, tokens and collection items. Those are important rewards, because you always have use for them. Buildings are not important rewards, because you can have only 6 of them and that's it. Sooner or later everyone gets 6 of them, there is no escaping that and there is no point of spending extra greens on speeding that up.I disagree on the rewards being lower for a newer player between a red and green/blue launches. The rewards for green/blue launches ultimately get you the alien legacy and the space travel monument which are like 12 nice astronaut academies for cost of a some low level launches. By the time you have completed both of those collections a player will be near level 60 and ready to be a top player in red launches and no longer a low level player in my eyes.
That's my point, green and blue launches are a dead end, sooner or later you'll get everything you wanted from them and focus on red. Therefore, as red are the long term goal, there is no point on spending greens on green/blue launch buildings unless you already have all the Planetariums you could use.