Bit of clarification, there are two apps being discussed here.
- One contains information about the flight, the crew, and the pax. This is where you'll see the asterisks showing MM achievements, birthdays (± a day), and status achievements. As @mikeyf notes, I believe it's the flight AFTER you hit the milestones. The seat boxes are color coded and depend on the FA's settings, but the "basic" is the standard seat maps (orange open up front, blue is open e+, white is open e-, grey is filled) plus black for GS and a steel blue for 1K. Additionally, FAs can select to view all status levels, including *S/*G. Connection info and PNR/SSR info is found here. I've never noticed PQMs, but that might be new.
- The sales app that you see pulled up when on the cart. As mentioned, it highlights GS/1K for easy identification for the free BoB in Y. This app also includes the onboard compensation, and some other goodies that are still in Beta.
In my experience, few crewmembers open the first app after boarding is complete. Honestly, I've forgotten to acknowledge the MM milestones before on particularly busy flights... I've also had my head bitten off for "exposing private customer info" when congratulating someone on 1MM, and people be visibly uncomfortable that I knew it was their birthday, so I can see why some may not want to even try.
And finally, the only reason I know of these features is because I find these things interesting (I am on FT, after all) and do some digging myself -- the userguides for these apps are not intuitive and I find myself teaching and learning from others about new features often. It would not surprise me if someone didn't know about the milestones, or what "3MM" means when next to a name. The apps are great, but documentation is poor.