In games like White Water, Addams Family, Ghostbusters, MM, AFM, etc, the pops aren't that valuable or important for big scores. They're not nothing, but they're not the centerpiece of anyone's scoring strategy. The same goes for most games, I think. What are the biggest exceptions?
Very important:
Lexy Lightspeed: Escape from Earth
Buccaneer
Only kinda important:
Guardians of the Galaxy (for Yaka Arrow and Antiquities Shop)
TNA (for a jackpot shot, sometimes)
The amber bonus on the new Jurassic Park might shape up to be kinda important, only time will tell.
What else?
PS: I'm not counting games where the pops are only valuable because they let you get more rollovers, like TOM or whatever.