Why does someone buy a Blue Ray over a DvD even though it's only 10% better? Why does someone buy a 6870 card over a 6850 card when it's only 10% better? Why does someone buy Premium gasoline over regular gasoline when it's not even 10% better?
They do so because they want to. And that extends to everything in our lives. We go to the grocery store and we're presented 6 different Ketchups, some cheaper, some more expensive. We buy what we want.
Why is it so hard for you to grasp that there are people who are willing to pay for that 10% bonus in STO just like they are at Target, Jewel, Ford, Wal-mart, and everywhere else we buy things?
How would you classify this type of Human behaviour? Of course in most of the examples you have something tangible to wrap your hand/mind around.
Here you don't even Own "that" ship or the starbase