Well since you asked, I think being part of a loose team which is working together for a particular outcome, an outcome that cannot be achieved in minutes or even weeks is very rare, if not unique, in computer games, especially one that allows the player to go off and do other things as he or she sees fit. The credits don't matter to me, they are just as means to an end rather than a way of keeping score. Up until now I worked hard enough to get the ships that I wanted to achieve a particular purpose, that meant I topped out a T6 and a Cobra. The latter really just being the means to get the former and to use it well (scouting out trade routes and the like). The T6 was a trader until I had enough cash in the bank to go exploring knowing that I had a sufficient stash to start over should it all go up. Once I had that I sold the Cobra, re-outfitted the T6 for exploration (it is plenty good enough for my exploration needs) and headed off. I saw no need in the foreseeable future for me to acquire more credits, a bigger better ship or to talk to other players.
Due to an incident involving a bored cat, a glass of beer and a keyboard I had to return from my expedition far earlier than planned. I looked at PowerPlay and I saw it was possibly an very interesting and subtle add on to a game which in many other ways is rather sterile with at its heart an economy that pretends to be dynamic but I don't think really is. For a faction to progress in PowerPlay its members must come together and co-operate and yet the numbers of such players and their global diversity means that there can be no organisation structure and certainly no command and control, there probably cannot even be an agreed definition of what the goal is at anyone point in time. I also saw the possibility that PowerPlay may breathe life into in dead economic system. For example if one of the factions closed all the black markets in systems under its control would that disadvantage the smuggling community enough for them to take up arms to do something about it.
So having seen what appear to be very interesting possibilities I decided to get involved. Having joined a faction I clearly now have the motive to communicate with other players, both inside and outside the game. My ships are marked with my faction identity so to some I have become a target to be attacked on sight. Thus my T6 is no longer good enough for some trade runs and I need a combat ship myself for when the opposition decide to come and play on my turf. Therefore I need to earn credits to fund these new ships and lots of them (have you seen the price of a well-specced Asp?). So in addition to my faction work I need to get that income rolling. Incidentally, on the subject of income, the fact that my faction pays very little does not worry me in the slightest, nor am I interested in the faction specific gizmos, both are irrelevant to the reasons why I chose to get involved in PowerPlay.
Apologies for the long post but you did ask the question.