Photo Challenge Blogs - Fun And Challenging OR Just A Money Maker?

I enter a few photo challenges at blogs that offer that sort of thing.  I post for the particular challenge that I think I can accomplish in the free time I have at hand.  I pick and choose the challenge that interests me the most and seems feasible in my environment and climate.  I may not get a chance to fulfill my self appointed obligation, so I miss out on some challenges.  

They make me think and use my camera at times I might not even think about it.  My camera could sit in the closet for a very long time, before I take it out to take photos. Maybe on a trip, or family gathering.  They make me post photos to my blog, stay up to date, and keep it active.  Challenges of the blog type peak my interest.............. taking more photos and the more photos you take the better you get to know your equipment, which makes you better at photography.  There is more to photography than just taking pictures, but participating in challenges will make you want to take better photographs.  Like those 365 every day photos.  By the time you've finished a year, you should be taking some awesome photos... right? ;)

Some 'challenge' bloggers make it fun, interesting and social.  Other's just plop a image on the screen, name it and call it the challenge of the week.  Sometimes, they drag out really old photos from their archives to name the challenge.  Some actually go out and take a photo to post for the challenge. 

I know, what's the difference?................ For one thing, one is just making money off blogging with all the Google Ad Sense or Wordpress's Ad Widgets, from how many visitors the blog gets.  The other is actually participating in their own challenge and encouraging others to participate.   One hardly ever comments on your photo post, but the other almost always does and, more than likely, so do the participants of their challenge.  One is impersonal, one is social and inspiring.  Some even offer contest challenges and you get to vote for your favorite photo, but the same people win the contests over and over again. They must know each other. 

I'm just saying... or asking.... which would you prefer?  Or does it matter?