It really didn't give more credits than a skilled fireworks player currently makes. In fact, someone scoring 6,000 in fireworks (in about 10 minutes time) would earn 1,200 credits which would have taken me only a little less than 20 minutes to get when the shells were worth 25 coins each. That means skilled fireworks players potentially make nearly twice as much as someone who's good at the shell mini-game would have made back when the shells were worth more. But the issue is that some people aren't good at fireworks (or can't play fireworks well on a laptop) so they're getting left out on making as many credits. Also, you mentioned that you were didn't like the shell game and you seem to have a particular affinity toward the fireworks game. I doubt that your feelings would be the same on this issue if it were the inverse.