I think Flick's punishment was more severe. It doesn't give a financial punishment but he can't find time in the match that week. Just think, your most important weapon doesn't come to training and Flick doesn't let him play in the match in order not to break discipline. This is a big threat to the other players. I'm sure everyone comes to training on time.
The fact that there're enough competition tobe in the first 11 player is already a thing that will push each player to perform to their best to stay or get into the list..when it comes to the punishment aspect, he knows most of them would be able to afford it even though it's a little bit...yet the best way to get them is by suspending him from playing the match because it something that pains every player if they don't get to proof their worth in a game especially in a team where the competition is getting tighter
in football as in other complex human organizations a sort of hierarchy is important
If the coach doesn't assert his being the alpha man, then its all over
it starts with the protests, and with the fact that the players don't recognyze him as a leader and everything gets complicated
in this case Flick did well