A/B testing is presenting information in different ways, to see which is more effective. The same is done on websites at times.
It has little to do with concrete rewards. It has to do with how info is presented (see the inline images). If more "huzzah" prompts folks to play more, they design around that premise. If having a lengthier delay causes folks like me to get frustrated waiting for BS screens and leave instead of playing more, they design around that premise.
You can't learn without gaining information, if you only present info one way, you keep yourself ignorant of the results of presenting info another way.
Have you ever thought, "if only I could go back and say this instead?" Here's a method of doing that, present "this" to others.
The resulting data informs future decisions.
They are posting this as a heads up so when you see on a livestream someone going through different screens than you do, you don't complain tha...