Well, and one more thing.
Not sure if this is a bug. But after I put the Marshmello dragon in the formation, the mission rewards for gold are no longer adequately issued. That is, for a minute of downtime, I receive conditionally 1 * 1e1100, and missions for 10 minutes of gold give me 1 * 1e1075.
Gold from missions, silver chests and time warps, like offline progress, doesn't take into account various active skills that would be in flux while running the formula.
So yeah, depending on where you are in the game and who is in your formation, the gold from those various sources would be less than from a monster kill.
Hence the various community requests to get rid of or vastly improve gold missions.